The strength of the Taranto attack as Britain is that you have to basically bring as many planes to the fight as Italy has eligible to scramble in order to ensure “mutual destruction” odds.
Assuming you always destroy the Italian transport off of Malta, you will leave Italy with only a handful of boats and one lone transport. With only one transport it is very unlikely that Italy can effectively take Greece and Gibraltar on the first turn, meaning that you can deny them a valuable objective early on. Sending one transport either way means it will take at least another two turns to get to the other side. (The solution to this for the Axis is Germany taking Gibraltar for Italy).
With only one transport, Italy cannot effectively threaten Egypt, which gives Britain much-needed time to fortify it with troops from either India or S. Africa.
Even though the UK’s navy in the med faces almost assured destruction (if the Italian counterattack doesn’t finish it off somehow, German planes will), you are banking on the fact that you make almost triple Italy’s economy. Italy’s paltry 10 IPCs mean that rebuilding transports will take a huge portion of their income. Until Italy achieves it’s NO’s, building anything larger than destroyers and submarines will be impossible without saving up IPCs for 1-2 turns.
The other advantage of this strategy is that by destroying most of Italy’s navy early the US does not have to build as large a navy in the Atlantic, which is a massive benefit given the task of facing Japan in the Pacific.
The other popular UK opener is to pull your navy back into SZ81 and possibly join with the India navy (that might be running away from Japan) and build up a force too great for even Italy’s combined navy to defend against. Then the US and UK both hit the med on turn 4 in a 1-2 punch.
