Some of them already accept alternatives to bitcoin like wankcoin.
I see do you talking about that full PoW SHA256 coin?
Only a matter of time when people will stop mining that and go back to Bitcoin,
than it will be easy to attack that coin with low hashpower too, and sites will stop accepting Wankcoin,
it really don't give you anything more that bitcoin can't.
While we think we can do.
And XXX now 100% PoS, see what happend when PoW blocks ended and PoS haven't yet started, the chain just stopped,
nobody could move it, nobody could attack it, because it consumes coin age.
So we could be sure it is secure now, XXX need 0% energy to keep up the network,
while with Wankcoin anytime miners will stop mining it, it will just stop, anytime the hashrate go below a hashrate level,
somebody will 51% attack it.
You can't attack XXX, only when you buy 51% of all the coins, but we don't think anybody is able to.