High-speed railway station is far from the city, so it is inconvenient to travel. Generally, ordinary railway stations are located in the old railway station, which is close to the urban area and has convenient transportation.
Although the speed of high-speed rail is faster than that of ordinary trains, it basically runs during the day, wasting the time during the day. The ordinary train follows the "early departure and early arrival" time from the departure station to the terminal station, so you can sleep in the sleeper without wasting time during the day.
After passing through the high-speed rail, some lines will cancel the ordinary speed trains in the same or similar sections;
For many ordinary people, they don't have to rush that time and don't want to enjoy a good ride. Saving is more important.