I have been reading and trying to learn about hones but I'm a little confused about what are called "barber's hones" and I've got a few questions.

1. Why do they never say what grit they are? If they are for touching up a blade are they something similar to a 12k?
2. Why are the only barbers hones I see vintage? Are these kinds of hones no longer made?
3. Finally, if these hones work the way I think they do, what's the point of using CrOx pastes and sprays when you can just do a few laps on your barbers hone?

Sorry about the basic level questions - I'm still working on getting a basic level of knowledge.