Does this benefit the bitcoin overall with XT?
No, whether you are pro or against the changes that XT brings, it's
very bad for everybody (except banks and governments, I guess) if Bitcoin would split up into Core and XT.
Do not lie.
Bitcoin XT is a fork of bitcoin core which implemented BIP101, the most widely accepted proposition for rising the blocksize. The way BIP101 works prohibits a split.
It's all about providing room for new users to utilize the blockchain.
Blockstream(Core devs) have the agenda of suppressing the natural evolution of bitcoin and moving users to their payment hubs and channels.