Signal doesn’t provide such open and easily found chat rooms.
It’s really much more a messenger (with group chats, but those you have to manually set up)
So it’s not an “open” place like telegram and with that not as attractive for advertising illicit services or products.
besides that, Signal is the technically much more secure variant. No discussion about it.
Not OP, but can only speak from my experience: Installing a second WM/DE usually messes up my install, as quite some stuff is just from one GUI framework, so I don’t have to have to much stuff installed.
Also getting rid of it afterwards always wasn’t as easily possible.
I completely get trying out a WM y firing up a VM. You could even just boot the live USB stick to check it out.
But changing my working install just to try something (and then have to clean it up again) wasn’t working out for me in the past