Good question I don’t see why it would be different between the various coins I’d imagine they would just rely on transaction confirmations before issuing the new tokens
I think since Bitfence is using the ethereum network then it's only normal to get a faster confirmation and Token issuing since it's still within same infrastructure, however I can't really establish the condition for ltc
I know some other projects that also pay nearly instantly when you pay with ETH, and they also use Ethereum network. It would be awesome if it also worked with the other payment coins.
I am also not sure but I have seen few projects delaying tokens distribution if payment is done using fiat currency. But we should ask this question in telegram channel to get confirmation.