Of course wallets dont matter this much. But payment gateway definitely does. I mean, this is huge thing for services/businesses/etc. Now exchanges, shops and any other projects could easily accept Bytecoin and other CryptoNote coins. This does matter.
I just havent got it how exactly this would work? Something like CoinPayments or what? How quickly can I implement this on my website, for example?
As it's said in the OP, a new payment gateway will be
capable of receiving and sending thousands Bytecoin transactions simultaneously
Why not make the same feature for GUI wallet?