What is the difference between onion and web?

Question

Computer networks

Hello. Is it true that sites in the onion zone are

1) more difficult to access
2) accessing the server where the data is stored is almost impossible for an outside observer, visitor, I'm not talking about the NSA and so on. Unlike the http protocol, where knowing the server IP, you can go to the hoster.

What are the possible security benefits of onion sites from the web.