The main differences between distros boil down to:

• init system
• default configurations and applications
• release cycle
• package manager

Most end users don't mess around too much with their init system and software configuration. With the rise of mainstream distros and application developers opting to ship desktop applications as snaps/flatpak/appimages, the last two points have less importance than ever.

IMHO, considering this, most of the discussions surrounding distros is relatively silly. After using Linux for almost 20 years at this point, I think I can safely say I could be productive on most popular distributions, with minor adjustments to my workflow.

For a new user? Just pick one of the main distros, that supports the software you need, and roll with it for a while. It won't make much of a difference. Distro hopping doesn't make one learn much outside using a different package manager.

Nowadays there are (less than $20) single board computers able to "run Linux" and decode 1080p videos like its nothing, so a perfect, plausible answer for your thread is simply "Why not a PC with Linux and another PC for Windows?". Even if GNU/Linux is decent enough for gaming/working needs nowadays.

Then again, you might be arguing like distros have specific use cases -- which is a straight up fallacy. Every distro is GNU/Linux at heart. Theres no such thing as "more useful" since you can simply remove packages/commands you don't find pleasing/"useful" and add/compile another ones yourself.

People use computers to accplish tasks. That requires running software on an OS, but nobody runs software or an OS just to sit & watch it exist. They run it to accomplish tasks.

Different distros mostly vary in how easy it is to accomplish various tasks. No one distro is the easiest for everything, so people make different choices depending on their needs.