I like not having to worry about potentially getting a virus or downloading software that will slow down the performance of my phone or my battery life.
Furthermore my phone has not even crashed once since I bought it. Crashing/freezing seems to be a problem that android-based phones experience quite a lot.
If your phone had viruses and crashed a lot, that kinda sounds like your fault.
The crashing and bad performance could be the fault of the manufacturer's stuffty rom, but if you buy a computer with stuffty bloatware are you going to leave the default OS?
No, you're going to wipe that stuff and install Windows fresh. (or Linux if you don't care about games I guess)
Why don't people do this with Android devices too? Just install a close-to-stock rom.
And the virus argument is bullstuff. If you installed a virus, that means you went into the settings, enabled the "let me install non-playstore apps" checkbox, and downloaded an untrustworthy APK.
Your solution for this is to remove the option for users to install non-appstore software entirely?
That is stuffty.