Barbers also trim beards. They will also help you decide a good look for what hair you have, even if it's shave, buzz with a fade, etc. Again, well groomed is more important than the actual cut.

For the record I shave my head. But I also regularly get compliments on my beard which is due entirely to having it trimmed by a barber every 2-3 weeks.

Most bald guys have hair just not that much on the top. Shaping the remaining hair in a fashionable way is imperative. Looking like George Carlin in his later years with long unkempt hair on the sides and a bald spot on the top is not sexy.