Gnome (EFL too?) pushes CSD. Everyone else prefers SSD.
Funnily enough that preference hit X11 too. When Xfce upgraded their Gtk version, as some of their own settings windows started being CSD. Looked rather jarring, IMHO.
Again, partly emotional, as I just got too tired of seeing dependencies on Gnome tools popping up in commercial apps I needed at work, and also little traces of Gnome's way of doing things here and there.
But mostly just being lazy and wanting my PCs to let me get on with work and play in the easiest manner. Since WSL2's introduction, giving me all the user space development tools and workflows I'm used to from regular Linux, Windows nearly caught up.
Seeing as X11 is officially legacy and Wayland IS the future, I've looked for the way to get that working like I want it. Obviously that will need me to write my own window manager (compositor), based on wlroots most likely. I've written one for X11 before, so it's not impossible, but the effort tips the balance even more towards Windows for me. Working for a Microsoft-happy company until a few years ago, I'd already written the convenience tools (hotkeys and window placement mostly) that I needed to be comfortable anyway.

Anyhu, it's all personal preference. And I'm not letting go of Linux the kernel, the bash shell or the rest of the command line environment. Just choosing the GUI and base OS that lets me get my PCs up and running comfortably the easiest.

???
(In particular, what do CSD and SSD mean in this context? In particular, what do these acronyms stand for?)

Pretty sure he means client vs server side window decorations. In other words does the app render its titlebar area or does the server control the rendering of things like minimize/close.

I'm not sure how this effects Wayland though. Wayland does not force this. And even Gnome which does encourage apps to use CSD needs to support XWayland. So...I don't see how there's a way around not allowing for SSD.

IIRC, Wayland core protocol originally stated that windows were responsible for drawing themselves in their entirety. Don't know the current wording. But Wayland itself does not really prohibit SSD.
To facilitate optional SSD there's the xdg-decoration extension where applications can state their preference. Unfortunately, Gnome will not implement it, so applications wishing to look OK on Gnome have to implement CSD, regardless of whether or not the application has anything useful to put into its header bar.
And some then don't bother checking for the availability of SSD with the xdg-decoration, and always draw their own decoration resulting in two window headers. I think Flutter apps still fall into this category.

Never heard of it. So i guess i'm not using it.

Pipewire, just like pulseaudio before it, and like systemd for that matter, is the sort of software that is often installed by default, and whose presence is generally invisible to the user, unless the user goes looking for it or something breaks. Therefore, if you're using a very recent desktop linux distribution, there's a reasonable chance you might be using pipewire and not realizing it.

Well i know my Mint machines use PulseAudio, as it's mentioned in fixing audio drivers on my chromebook and as a mixer. And i haven't really updated any of my distros for a few years, so i'm still on Mint 18 i believe.

I totally get that. Moving to Linux full time a decade ago and it was more a case of mentally letting go of Windows than it was anything logical. I still kept a dual boot for the longest time, but mainly for games that didn't run well on Linux. Now days, that is pretty much not an issue.

Edit: And it was MS's total telemetry crazyness that really pushed me over the edge. I really don't want to run it at all because of that.

This is one of the many reasons I refuse to use steam, and have become more and more distanced to gog as well due to their strong push towards telemetry-focused galaxy. That shite is exactly why I gave up Windows many, many years ago, so the last thing I want is to add that to my otherwise independent operating system. GOG pissed against the wind by trying to copy steam, and now also starting to embrace DRM.

You and me both. I have 1,200 games exactly on Steam, and I have an additional 759 DLC. One day I was thinking... I really don't own those games. If Steam failed, I lose them all.

I am catching up to Steam with GoG purchases and I currently stand at 279 owned games, and the ones I really like end up on my NAS for archive purposes. Just wish some like Subnautica would make it to this platform. I really like that one.

Edit: Also note I checked my Steam account value and it was showing about $14,000. That is a good chunk of change to lose if I did loo. See attached screenshot. So yeah. Happy to send GoG that money in the future assuming they keep their same policies.