- Pros:
- system trays applet already works out of the box (still customizable to some extend at least more than gnome system trays)
- very good support for Wayland and VIDIA GPUs
- easy and quick to customize and you don’t have to deal with CSS if you don’t have much time to waste
- better integrated with KDE’s softwares (Kdenlive, KDE connect, Konsole, Kate, Elisa…) which is my opinion some of the best softwares for Linux even better than Windows’s in some cases
- friendly community (mostly)
- Cons:
- you have to use KDE with Krohnkite


The main reason I hear is that it maximizes screen usage and helps avoid/limit the tediousness of having to manage windows.
Not what you’re asking for, but I’ll give you my perspective as someone who’s tried tiling on and off and overall don’t like it.
Cosmic is exciting in this regard since it aims to be a fully-featured floating and tiling environment. You could just toggle between them as necessary (or have them on separate workplaces). You also get much better portal support.
Number 2 is an implementation issue. Dialogs should be floating by default.
Number 3 is funny to me, because that’s exactly the experience I have when using a floating WM.
Khronkite is worth checking out in relation to this point. It requires minimal setup (keybinds + choosing tiling layout) so it’s a good introduction to tiling WMs. I’m guessing more experienced users would prefer more control but I like it just fine.