Why is a tiling window manager so important for dev work (but not for anything else)? I am a dev and I can never wrap my head around why anyone would want to spend time on tiling windows, it looks so tedious.
These days I'm on macOS not linux but my desire for that kind of control and speed remains; fortunately tools like BetterTouchTool enable this really nicely, and I get the best of both worlds: nice mouse-driven control when I want it, and a quick/easy way to throw a window where I want it the rest of the time (i.e. most of the time).
(I'd also say, addressing the parenthesised part of your first question, that for me, this isn't just about dev - this is a general preference; for some tools, e.g. the GIMP, tiling's a bad fit and the mouse is where it's at, but in general, if I can keyboard it, I will.)
So I've got a whole bunch of hotkeys doing things like "maximise window", "put window in top-right quadrant", "put window on display 3, taking up 1/3 of the width of the screen at the right and at full height". That kinda thing. This allows me to quickly/easily set things up as I want (not _automatically_ but that's fine for me in practice since the world and my needs are always in flux.) If you dig into it you can do some fairly powerful things... E.g. you can set up named triggers (i.e. actions not bound to hotkeys) which you can then call from AppleScript triggered by hotkeys (or, if you want, triggered externally by, e.g. Alfred, though I don't do that); the AppleScripts can maintain state between calls, so I have some hotkeys that move windows in cycles, e.g. "maximise the window's height and push it all the way to the left, and on each call cycle its width between 1/6, 1/3, 1/4, 1/2, 2/3" - stuff like that.
It's true you don't get "real" tiling with this - but as I say, for me, it satisfies the "why" of tiling WMs, without doing the "how". Hope that makes sense.
Weird, I always ask people the opposite. Why would you spend time manually positioning windows when the window manager can do it for you?
What is "tedious" about tiling window managers?
In a tiling WM full screen is the default. I never have to manually full screen something, it’s automatically taking up the whole screen. I usually have it in tabbed mode, so all new programs are just full screen in tabs. (And split view is just a hot key or two away)
Really though my favorite thing is the easy multiple desktops. Win+4 is always my chat program. Win+2 is always my ide, win+1 is always my web browser. I never have to mash alt+tab a varying number of times. and more importantly if the second desktop is actually two programs in split screen, it’s still easy to switch to and from. Otherwise I frequently find myself looking at one thing in full screen, then having to alt+tab multiple times to bring two half-screen programs back to the front.
I’ve tried to install various windows tools to either provide hot keys to virtual desktops, or otherwise replicate my tiling WM setup but nothing seems to be quite as convenient to me. I feel like I waste so much time alt+tabbing and getting things where I want them whenever I’m in a normal WM. In i3 it’s all either already the way I like or it’s 1-2 hotkeys to fix it.
It automatically makes the window you're using take up 100% of the screen. You can also switch between tiling and a maximized view in pretty much every tiling wm. Also, there are usually multiple desktops (or even better, "tags" like in dwm) which allow you to easily switch between applications in any of the different tiling modes.