The fact that it isn't Windows and most of us had Windows shoved down our throats for years.
Therefor the workflow is different than what we're used to and there's a learning curve.
But the curve isn't as steep as most people like to believe, many distro's can be used without even touching the terminal.
Seriously, many user friendly distro's exist these days.

My advice would be to create a Ventoy USB drive, slap some iso's from distro's that interest you on it and give them all a go in a live environment.
Pick the one you feel most comfortable with and install it.
That's how I made the switch almost a year ago, haven't looked back since.