Though today we have new chrome and other alternative to Internet explorer, still I use it the max I can. There are several other reasons but below are most important
It utilizes computer memory at its optimum level
The apps like Microsoft Teams, crash on other browsers, especially Chrome
It does not allows unnecessary pop-ups
It prevents me from any fake javascript program that tries to take access of my system, by putting some false peemissions
However we have a new Microsoft Edge now, but still Internet Explorer makes you reliable and safe than other browsers.