1. That would be relevant if talking about mass adoption but for the enthusiast market, when people want something e.g. custom songs in beat sabre or to play quake, we are delighted to use Sidequest. I'd happily sideload any app that I could experience some value in using with a headset but it's only things like Google Earth that make sense to me. As far as I can tell, for something like a spreadsheet, learning a new keyboard shortcut is more world changing than what a headset can offer.

2. I just don't rate them. The magic of 3d headsets that differentiates them from 2D for me has been "presence". To stand in front of a massive temple in Skyrim or something and feel like you are there, it's special and can't be replicated in 2D to the same extent. As soon as you get into a focussed state e.g. a game loop churning out iron daggers to level a skill, presence doesn't matter. Your area of attention is quite small and having a headset on is just a pain in ass. 2d apps are in the latter category for me.

My basic rule of thumb is that if you don't already render the content in 3d on a 2d screen, "spatial" doesn't have much to offer besides gimmickery.