this one is an oldy. It's based on the norton commander many people remember from the dos days (that's disk operating system, not denial of service which is almost invented by the same company but that's a newer version.)
If you have trouble learning the linux commands at start, this can help. It allows execution of programs by double clicking on them and navigating directories visually

I don't think it's used a lot anymore, but I don't really know about that. It could provide an entrance to the command line for people who want to learn slowly.

Yes that's true they should know vi, and so should Linux users.

Because Linux is based almost exclusively on configurations stored in text files, the ability to edit them without the knowledge of the potential impact can be quite dangerous. There was a time where a stray ':' in a host database file could bring an entire network down. Most Linux files of this power that are so sensitive are restricted to root-only access