It hink the other comments already made good points, but just to complete it for me:
- There's very little learning curve with i3. After setting/learning 2 or 3 keyboard shortcuts you're good to go. That makes the adoption a no brainer.
- 99% of what I do is done in a shell (code, sysadmin) or a browser (read doc, write doc). That means I often need a lot of shell windows all over the place. The tiling really helps here. I could use tmux/screen for that (that's what I did before i3), but I often already have tmuxes on the remote boxes I ssh to, and the inception makes navigation harder.
- it's fast, there no animation or latency whatshowever. I can very quickly open a shell, ssh, run a command, close it, etc.
Most of these could be done with any keyboard oriented tiling wm, I just so happen to use i3.
- i3 treats individual monitors as virtual desktops instead of having them stretch across all monitors which makes it easy to shift say a workspace with a browser or a chat app into a secondary monitor without losing the current task or having to rearrange everything.
- i3 lets you define keybinding modes that work much like modes in vim
- i3 is very simple and comprehensible its about as non magical as can be making it using it predictable and simple
