As a developer I love that git gives me the ability to create my own repo anywhere on any machine, just with git installed. Repos can be synced and patches exchanged in numerous ways and any decentral copy is a full backup of everything.

But as someone having worked in larger companies, there are huuge red flags with this that you wouldn't want the wrong people in your company to know about. Fully functional repos anywhere means central control is impossible. You can't just limit access in any meaningful way, you can't control info leaks, if someone can carry out a git clone on an USB stick. And full repo with history means that you always know everything about the work performance of all colleagues, past and present.

It's possible and we use it at work. Most major source control servers that support git also support user and role-based control over PR merges, force commits, etc.

There's little difference between a user that has a copy of the source as SVN and that of git, other than the git client itself allows the user to manage their commits on their local computer.