The issue is that users might object to subscribing to a community on a particular instance. I guess it’s not the end of the world, you can always unsubscribe but I can imagine some people being very upset to be associated with certain politically leaning instances or worse.
I use a 42" 4K monitor. Same working area as 4 x 21" 1920x1080 screens but more flexible. Been doing so for ~10 years. When my old 39" 4K monitor broke I used 2 x 24 inch monitors + laptop screen for a while but I ended up buying another big monitor instead, it’s just so convenient.