Main disadvantage is to do anything you have to contact them and most are clueless for anything other than i’ll call our flight desk. Cant upgrade oneworld segments ( i.e ba miles to upgrade Aa segment I think) , and too many have never heard of ita matrix or when they have cant pull up the fares even where aa or ba can and insist ita matrix is always wrong.
On the plus side I have found they can be cheaper - my upcoming flights dub-lhr-mia-gcm then pty-mad-lhr-gla were 200 quid cheaper with a glasgow ta then ba could pull up on the phone, even after credit card charges and commission. Find a good indy TA and educate them seems to be the best bet!
Ps, if you are in dub, shouldnt you be flying to hnl every week for the rest of the year!