I’m really sorry you feel that way, but I assure you that the mention of the BuddyPress is there, just below the dependencies, in the Product page.
I just realized it’s missing from the Documentation, but I’ll fix that there asap.
Using BuddyPress? Then you’ll also need our bbNNS/BuddyPress Bridge. This is because BuddyPress restricts users from accessing WP and bbPress profile screens, keeping your visitors from changing their preferences.
Once you install the BuddyPress bridge, you’ll see the Digests option in the Profile > View and Profile > Edit screens from BuddyPress. You’ll also be able to control Group Forum options in Admin > Settings > Forums > Email Notifications, or alternatively in Admin > Settings > BBPNNS/BuddyPress Bridge.
Currently, the Bridge does NOT provide the fields in the Registration page, but that’s coming up soon.
As for the topic notifications, please check your spam folder and let me know if you don’t see them there.