The important difference between bromine tabs and bromide products is not the bromine vs bromide factor, but the presence of hydantoin in the tabs, which combines with bromine to allow solid bromine tabs, in a manner similar to the way that cyanuric acid allows solid chlorine tabs.

For reasons I don't understand, hydantoin apparently prevents the conversion of bromide to bromate, a process which is the 'exit door' for the endless "bromide + chlorine => bromine => bromine + dirt => bromide => restart" process.

However, your final statement that you may not have to drain the pool, if you use bromide products instead of bromine tabs is correct, I believe.