as an OT, yes it's worth it
OT's can be specially trained as hand therapists. even if it was tendinitis, it would help and certainly if its weakness from MS they can help...and there is much more they can do than some hand exercises
but only you can decide if the time you would have to put in and the difficulties you might have getting there would be worth it. a big part of the success or failure of any therapy you might do depends on the time you devote to it outside of your appointments (home program!) and the lifestyle changes you are willing to make to accommodate for your new normal.
i'm biased of course, but having spent quite a bit of time in PT as a patient because of injuries (back injuries x2, bike accident) and MS, my PT worked wonders for me and i am still thankful for his help. i am currently back in PT for rotator cuff tendinitis and ulnar nerve entrapment, so i get how time consuming it can be. why not try it twice a week for a couple of weeks to see if its going to work for you.