Anyone used besichtigung.net for a room in Hamburg? Trying to verify before booking

Hi everyone,

I'm an international student moving to Hamburg (Harburg area) this October and found a room listing through a site called besichtigung.net — seems to be a viewing/appointment booking tool rather than a listing site itself.

Has anyone here actually rented through this platform or dealt with a landlord who uses it?

Trying to figure out:

Is this a legitimate, commonly used tool in Germany?

Any experience with deposit refunds through this process?

General red flags I should watch for during the video viewing?

Would appreciate any first-hand experience before I commit.

Thanks!