People already largely answered on many points, but I'll just answer on one point:

> unsecure

How is security defined? What is your threat model? If your threat model includes includes running random native binary blobs from random places like Android or iOS does, then yes, you can definitely consider it unsecure.

But that's NOT the target paradigm here, and if you consider it is, you're throwing away 90%+ of the GNU/Linux distributions out there. Last time I checked, running GNU/Linux on servers or desktops wasn't considered bad practice, quite the opposite.

Instead, it may be more secure than iOS, depending on your usage, because the paradigm is to install only opensource software that you actually trust.