You must not have small hands.
The distance from your thumb to the top of the screen, where Control Center is activated, is farther on the 13 mini compared to the SE. Because the top of the screen on the SE does not start at the very top. This makes the SE much more comfortable when you're trying to reach the top of the screen while holding the phone with one hand.
Also, you're comparing a phone with a home button (SE) to a phone without a home button. The SE doesn't require Face ID, which means you can make it so your phone doesn't lock instantly when you put it to sleep. You can make it not lock for 4 hours with Touch ID. Lastly, not everyone wants to have to look at their phone to authenticate stuff.