Some notes from someone who has experimented with this for years - with zero gravity chairs, beds, floors...
- having your hands elevated above chest height sucks after a few minutes. The Altwork and Ergoquest workstations suck for that reason, and you _need_ a split keyboard if you don't want numb fingers.
- not moving sucks. I think I've hurt my neck and back (and throat) more by doing this than I'd like to admit
- for short periods of time, and when you can _actually_ relax (side projects etc.), working in this way is divine.
YMMV.
Side note - I discovered OP Andy Matuschak around 3 hours ago while pimping my Obsidian config, and have been the biggest fan of @msgsloan's vim Todoist plugin for years.