Why browser makers might not want to cater to web developers wanting to use a keyboard on a platform that is used at 99.9% through touch controls, platform on which we both know they neither develop on (when is the last time you made a website on your tablet?) or even test on, is indeed left as an exercise for the reader.

Testing websites on actual mobile devices is generally advisable. Testing them in a niche browser, perhaps not so much, but more people will if that browser makes it easy.