(No provocation)
I see these reasons:
- newbie
- lazy (don’t wanna edit config files etc.)
- unique features (like assistant/toolbox, some optimizations like in cachyos)
- wanna check how different systems are set up (that’s rather distrohopping)
Personally, I used manjaro i3 when I was beigginer and wanted to see how tiling WM should be configured (check out ranger config, for example). But after some time, I don’t see reasons why not to just customize pure arch (same with debian and debian-based distros).
I consider that important knowledge for just using and troubleshooting your system, and one of the great reasons to go through the installation process - knowing what you’re using and why means when you want to change the behavior of something or figure out why it broke, you’ll know what software to look for.
Not just something to do for fun, or to have precisely the right things, but so you understand what it is you truly do have. This isn’t to say your approach is invalid, but for me it’s a reason to recommend Arch for people who want to go through the learning process.