Hiya, I've used beta books. I'll try an answer your questions.
How is it more private and safe? Can you explain what are the safety precautions used to ensure the ms is private? Does the website have access to my ms, or is it restricted? When signing up, are the terms that ensure the website can't share my ms?
It seems fair private and safe, but I mean, I tend to use Google Docs otherwise.
- When beta readers read the uploaded ms on BB, can they make notes directly on the document? And just so I'm sure I understood, they can't download the ms - it just stays on the website and they read/edit from there?
No, they can't download, and no, you can't make line by line. For me this is a deal breaker as a reader, though not as a writer. I almost always do line by line.
I do enjoy that you can easily read on your phone, loading a chapter at a time.
- So they can't make notes as they read on the document? (for example, on word when you can highlight a sentence/word and comment on that specifically, or when you strike certain words and recommend another word instead)
Uh, nope, sorry.
There are two main reasons to use betabooks imo.
First: it gives you access to the monthly beta swap group if you sign up. That means you get 3-4 other people who you're agreeing to swap reads with. However, the one downside is they try to pick different genres, so YMMV for how useful that feedback is. Suffice to say my philosophical high fantasy went down like a bucket of sick in my group of Thriller, Inspirational Romance, and Chick Lit writers.
Second: Gives you access to the Betapool where if you ahve a completed book, you can get up to 15-20 readers of it, usually. This is very valuable, though I've never done that because I prefer a bit less feedback.
Also as before it's easy to read on the phone and update with different versions (keeps the old versions.)