Most of us do what works for us and/or what we were taught to do. I know ppl who very successfully sponsor lots of ppl and never crack the BB. I tend to use the BB, 24hrs A Day, Daily Reflections, the 12&12, several Emmet Fox books and a couple by Eckart Tolle. Some people use only the BB.
If it works, who am I to say someone is doing it wrong? The truth is both Dr Bob, Bill, and a lot of the early AA "teachers" like Clarence Snyder in Cleveland did I find none of them sat down with their new guys and read the book together - yet that's become a thing in the past 10 or 20 years to do.
Live and learn, experiment, and seek God with your sponsees. I've found God can come to us in a LOT of different ways and through a lot of different books and processes. The steps in the BB are my core but I sprinkle in what I've learned and uncovered during my exploration too.