It's very obvious that you don't have to be able to buzz to be a good player. There are so many good players out there who don't or can't buzz, and all it takes is one to prove that it's not necessary.
However, there are some very famous players who do buzz. I'd like to make a list of these people for the second edition of my first book. I'm wondering if I could get some contributions of names of these players form TPIN land. If you know of any famous trumpet players who, for sure, do lip buzz as a regular part of their daily practice, then please send me their names.
My own, personal approach to lip buzz is to use it as a model, a guide that I follow on the trumpet. I don't use it to develop strength. Instead, I observe the lips, on their own, doing their thing. Then I try to emulate that on the trumpet. In the beginning, this helped me re-learn how to play. Later, after all my changes had become ancient history, I used the lip buzz to show me things that I would never have learned without it. The most recent of these has been slurring down on large intervals. To fix this problem, I observed my buzz, in the mirror, while slurring down on large intervals. I realized that there were things that I wasn't doing on the trumpet that I was doing on the buzz. Fixing the slur was just a matter, at that point, of emulating the buzzed slur while playing the trumpet. When used as an example, the lip buzz can show you things you never knew about your own playing.