I tried beta blockers back in the day and they did nothing for migraines for me. They did put in me in a permanent emotion-free fog, though.

Went off them and switched to Depakote (valproic acid) which did help a lot.

In recent years I've been able to lower the dose of the Depakote down to only 250 mg per day (of the extended release version). At my worst I was at 1500 mg per day (regular version, before the ER became available; I think the dosages are a bit different between ER and regular). Depakote is not without side effects, but I've able to do many long bike rides while taking it.

Of course, I'm not a neurologist so I don't know if there is a reason why your doctor feels a beta blocker is most appropriate for you.

FWIW I've never been able to take the pill because it made the migraines way way way way way worse for me, among other negative side effects.