difference is you dont need a third party tool to change the thing, if you're unhappy with the thing, you change the thing out itself, you are not stuck with it.
genuinely curious since I've never tried or even considered it. What happens when you have multiple desktops installed, and assuming it doesn't cause issues why would a person want to do that?
Typically your display manager lets you choose which environment you want from a dropdown menu. It’s responsible for helping you login and taking you to the desktop.
And you can have multiple login screens if you like. I’m not sure why I would typically do this.
openSUSE pre-installs IceWM, for example, even if you select a full-fledged DE during setup, so that if your proper DE should ever break, you still have a (very minimal) GUI to do your troubleshooting in.
There's no added value to having multiple desktop environments, so almost no one would want to. A lot of applications use DE sensitive configurations and there's potential for conflicts as well as libraries incompatibility. Which can result on paradoxical and bizarre behavior from some graphical apps. It's odd that it happens but it's also not something devs plan or account for, so they aren't even considered bugs. You don't install multiple DEs at the same time unless you're purposefully trying to break something or you don't know better.
The only use case currently is choosing between a DE with X or one with Wayland. But even that one could fuck your system.
For example, opening cinnamon experimental Wayland makes all my flatpaks stop working until reboot. Why? I don't know, nobody knows. But if I keep using Wayland after reboot they work. If I change to regular cinnamon, they break again until reboot, when they get fixed as long as I keep using regular cinnamon. It just be like that.
You can choose on the login screen, works well, but it gets confusing if the whole Desktop gets installed: example GNOME comes with gnome-terminal even if there is already xterm or KDE Konsole on the system
You can have a computer with multiple users, one prefers gnome, the other kde. Say, they also want to access the computer through cnc, but these are too slow for that, and one prefers windowmaker, the other enlightenment. It works just fine. You can run all these four at the same time.
It did more than "a few colors", compared to today's fancy modern theming systems it was def rudimentary, but with a single click Win 98 would change colors, the cursor, the entire sound pallette and even button images iirc. I was particularly fond of the Computer theme and the Space theme lol
In my opinion, it peaked in Windows XP. XP's themes were way more customizable than 98's. You could patch the uxtheme DLL (disable the signature check) to allow third-party themes.
They weren't though... I used to love the stardock stuff especially. But they were objectively inferior. I also couldn't run hyprland or sway with nearly every part replaced by an unconventional replacement like the friggin notifications daemon for example. Even on Plasma, i could literally replace the entire shell. And even on GNOME, I could add an "extension" that essentially replaces the GNOME workflow.
As much as I enjoyed those days of windows customisation, it was far too shallow compared to what i can do on a Linux setup. Will i do all that though? Probably not, i like my Plasma setup as it is right now.
i'm talking about being vastly superior to the built in theme options in windows since it implied third party tools were "bloat" instead of being genuinely useful.
Got to remember that most windows and Mac users aren’t even aware of the bloat. I don’t know how many times I’ve gotten on my mom’s pc that she said was going slow and found countless extensions, tool bars and off brand programs installed.
Between her being in her 50s and her grand kids hopping on and clicking everything, nobody knows or gives a damn.
Why is everybody so obsessed with tweaking and customizing an OS?! My systems are pretty much vanilla and apart from the file browser I hardly use any active OS features.
I remember in XP, Vista and 7 using the UXtheme dll mod to get third party themes. First the loss of the sidebar then the drop-off of themers. I skipped 8 and by 10 I'd had enough. Didn't really come back to theming until I made the jump to full-time Linux in 2022. Theming support being there by default in KDE is amazing. I miss the 2007-2018 themes but Oxygen keeps me happy for now.
The uxtheme thing was great because it was pretty powerful, and since it was just the standard theming system built-in to Windows, it was more reliable than theming systems that required third-party apps (WindowBlinds being the most common one).
Apparently uxtheme patching still works on Windows 11, but I haven't tried it.