Enabling browser userscripts on Android is not an evident procedure for novice users.

It's annoying if people do want this functionality to change how web pages behave, e.g. they want to fix a broken banner on mobile that doesn't have max-width: 100% but instead crops off on the page.

At this current time, Firefox changed their engine so that it supports only a limited set of add-ons and you'd have to use a nightly build in order to enable other add-ons such as userscript ones.
Chrome doesn't accept add-ons/extensions.
And there's the JavaScript trick but again, not user-friendly.

It's just annoying.