Based on my limited knowledge of chemicals (I mostly did equipment repairs, but still had to know my way around the chemicals), as well as knowledge attained from talking with customers, I believe that one of the big selling points of bromine is that it is much less harsh on the skin compared to chlorine.

I've never had a tub so I can't say for certain, but I also believe maintaining bromine levels is easier than with chlorine as well.

My bosses really pushed for bromine for all of these reasons, and probably more.

You could also look into alternatives. Some people run saltwater systems!