In the plot setting, there are two best ways to restrain Kyubi no Youko: Senju Hashirama's special wooden escape and Nachibo's Saringan's illusion ability. Unfortunately, Watergate does not have these two special abilities, so it can only choose to limit Kyubi no Youko by blocking ghosts.
As a life form created by Ootutuki Hagoromo using chakra in ten tail, bijuu has great strength and vitality, and it is not easy to suppress bijuu.
Because Kyubi no Youko is the product of chakra's materialization, it has huge chakra capacity and long life, even Watergate can't compete with Kyubi no Youko for chakra capacity and vitality.
And there are two better ways to deal with Kyubi no Youko set in the plot:
(1) Senju Hashirama's Mudun can absorb Kyubi no Youko and chakra, making Kyubi no Youko weak. Unfortunately, after Senju Hashirama's death, Muye Village could not find any ninja who could use Mudun Ninjutsu, and Namikaze Minato's physical condition was not suitable for transplanting cells between columns, so he could only seek to use seals to deal with Kyubi no Youko.
Although Namikaze Minato mastered the flying Raytheon, he could not effectively suppress Kyubi no Youko, nor could he suppress Kyubi no Youko with Senju Hashirama's stunt "Mudun Ninjutsu". Therefore, he can only passively seek the effect of sealing ghosts, so as to minimize the damage of Kyubi no Youko to Muye Village.
(2) In addition to Senju Hashirama's wood evasion skills, Uchibo's kaleidoscope sharingan illusion can also temporarily control Kyubi no Youko's actions (both Uchibo Madara and Datu used the illusion ability to control Kyubi no Youko's attack on Muye Village).
Namikaze Minato, on the other hand, is not good at this special illusion that needs to be shared. Namikaze Minato naturally wants to settle for second best, and uses ghosts to seal this skill of killing one thousand enemies and damaging one thousand enemies.
Namikaze Minato has consumed a lot of chakra in its earlier fight against Kyubi no Youko and invasion of China, so it has no chance to use other skills with less side effects to deal with Kyubi no Youko.
In order to limit the fighting capacity of ninja, Naruto introduced the setting of chakra. Once the total amount of chakra used by a ninja in a battle exceeds its carrying capacity, the result is that the ninja dies because of the excessive consumption of chakra (such as Payne's attack on Kakashi in Muye Village).
For Namikaze Minato, since he can become Huo Ying, he is naturally not afraid to make sacrifices for the village. At that time, in order to divert Kyubi no Youko's attack on Muye Village, Watergate used Raytheon many times, and the consumption of chakra was close to the limit of Watergate. Coupled with the battle with Turkey, it is impossible for Namikaze Minato to choose other more effective but skillful methods to deal with Kyubi no Youko.
Watergate actually learned a lot of powerful sealing technology through the whirlpool family. However, after a long and fierce battle, Watergate has been unable to introduce other skills that consume chakra more.
After Watergate solved the problem of borrowing soil, there were few chakra left, and there were not many skills to restrain Kyubi no Youko in the early stage of the plot. As a result, Namikaze Minato didn't have many other better choices, so he could only launch a ghost with high success rate to deal with Kyubi no Youko.
In order to let Naruto be blessed by the protagonist's aura and to have a strategic balance point, Watergate can only sacrifice himself to complete the previous task.
Bijuu is used as a strategic deterrent to balance the Ninja villages in Huo Ying, so the existence of bijuu Point has a great influence on the comprehensive strength of Ninja villages.
Under such constraints, Watergate must consider the macro-strategic gains and losses brought to Muye Village after the complete elimination of Kyubi no Youko (of course, it is unrealistic for Watergate to completely eliminate Kyubi no Youko from the perspective of bijuu's setting), so Watergate adopted a more compromise method to solve the Kyubi no Youko problem:
On the one hand, half of chakra in Kyubi no Youko was sealed in Naruto's body, making Naruto a pillar force in Kyubi no Youko, and maintaining the strength advantage of Konoha Village in bijuu, which was basically the same as other villages.
On the other hand, Naruto can reasonably gain the protagonist's aura, paving the way for the subsequent development, and at the same time forcing Muye Village to continue to protect Naruto's personal safety, because Naruto is the pillar force after Namikaze Minato's death.
Watergate should have been the safest way to solve the Kyubi no Youko problem in an emergency.
Watergate chose to use the ghost seal to deal with Kyubi no Youko in order to maintain the bijuu balance between Ninja villages as much as possible, so that Muye Village can continue to maintain its advantage, and at the same time, the first hero can also be blessed by the protagonist's aura.
After all, Watergate is only a supporting role in the early stage, and it is impossible to occupy too much plot content. Kishimoto also let Watergate leave in a relatively reasonable way in this way.
Finally, to sum up, I personally think that Namikaze Minato does not have Mu Dun of Senju Hashirama and Shalingen illusion of Neiguang, so it cannot suppress Kyubi no Youko in a simpler way. Besides, there is not much left in Watergate chakra. In order to keep the strategic balance of bijuu's forces in Muye Village and let Naruto, the first hero, win the leading role, he had to choose to use ghosts to deal with Kyubi no Youko. Please forgive me if the analysis is not in place. If you have any other ideas, please leave a message to discuss.