All good. FWIW I have neither downvote rights on HN, nor insight into the way other HNers think - so it's all quite speculative.
WRT bluetooth peripherals -- I used to feel this way about mouse, keyboard, car, and in-one-ear headset. My position on all has changed 180° over the past year or two. Not so much the grandmother conundrum, but the performance/latency, bother to charge or replace batteries, and general swankiness.
For gaming apparently BT headsets (and presumably mouse/keyboard) are too laggy, but for workplace convenience it's hard to go past them. Buy your grandmother a spare set of batteries for the third drawer, and consider that my rinky little Logitech 2 x AAA mouse is running on original batteries some 14 months on. These things are amazingly power-conservative. And even just one less thing to plug in when setting up a laptop (I travel a fair bit) is hugely appreciated. I simply wouldn't countenance a return to a wired USB mouse now for business use. Similar experience with BT headsets, and in-car use -- difficult to consider not using that tech now.
MS may well be working towards this area -- it's not a novel idea, certainly, and I recall about fifteen years ago people touting the benefits of thin client workstations you could carry around with you. Unfortunately keyboards and screens had to be provided at the other end, and few workplaces considered this convenient (compared to, presumably, just issuing laptops to mobile users, outright declining a BYOD approach, and/or enforcing a SOE). It's all one big cycle.