I think it will be no surprise if LTC take the lead in the micro transactions sphere. One of the key aspects of the cryptocurrencies is the low fee per transaction, witch in turn I can't say the same thing about BTC or ETH since the networks are clogging more and more this period.

I guess we'll have to wait and see how the new scalability updates on Bitcoin & Ethereum preform, but other than that LTC can take the lead.