As to that, I cannot answer, but I read an article about "gentlemanly conduct in the ring", which related to the formation of the Queensbury rules some time ago. Backhanding was rasied in it.
From a technical perpesctive, they may seem to flow well in your combinations, but from a defensive point of view in boxing, they are a poor choice.
Hooks will land on the target or miss, and then the hand has a short journey back to the guard position, that is in a more or less straight line (depending on were and if the hook landed).
With a backhand, if you miss, your hand can dangle out in mid air, and leave you exposed. Whereas a hook ends inside, a back hand ends outside, and the journey to guard position can be longer, if only for a second. If backhanding with the lead hand and you miss, your momentum can leave you more square on. It is not the best punch to throw from a defensive point of view. It can leave you vunerable. And even if you do hit, you can injure yourself, as most gloves don't offer much backhand protection.
At the end of the day though, we can talk about this until the cows come home, but it won't change the rules of boxing. Rules is rules, as they say. Backhands are illegal in boxing. I do believe though, you are perfectly entitled to contact the AIBA about this. But they have a team of full time medical professionals and safety officers working for them, so if they have outlawed it, they must have good reason for it.
"Let your food be your medicine, and your medicine be your food"