Sharding in blockchain is very early and a long way in the future. Meanwhile Vitalik also proposed Plasma for Ethereum blockchain as a scalability solution . NEO working with trinity And of course LIghtning Network for Bitcoin . Out of all these as a payment gateway i personally believe LN will do the best. But an on-chain scaling with sharding will be really interesting .
I think sharding is native to blockchain if it happens , but for now on and off combined solution is workable for Bitcoin , at least in near terms.