BCH I think is used on this read.cash platform for payment, its doing well, for me its a shit coin though, but as of now I think it is functional with good volume to be accepted as payment.

Lots of options should be there actually, but this Tesla guy is hyping up Bitcoin with this move, his intention is not anabling crypto payments for those cars, its just create hype on bitcoin, that's all. Why he can accept payments in ADA, XML, any stable coin, ETH (ouch the fees), DCR (decreed), Atom why even HIVE right?

BTC is ok he can accept payments in BTC, its cool, no problem, but he is doing it as advertisement for Bitcoin that's all... he can advertise Doge coin also, accept it for payments why not?