I'm actually working through the same school of thought with my UX team. Front end design is complicated these days. But the investment in native app development is much more heavy then creating a mobile-responsive (playing nice) experience as you know. My UX team has taken the approach that anything we design must be designed mobile-first, because desktop is a simple given.
But when some douchebag calls me on Google Voice, the responsive versions need to enable me to block the caller just like the desktop version. It should not hide that feature just because I'm on a tablet or mobile phone - which is what it does.
At least I can get to the desktop UI version on an iPad. I cannot with an iPhone. This situations happens far more often than you'd think. Like mobile versions of web sites where the ability to comment is disabled in the non-desktop version, etc.
