The other important thing to note here is that btcpay appears to allow us to implement the complete Counterparty feature set (send/receive, trades, bets)
Unfortunately not. You can not really have bets, and the orders involving IXC would be somewhat limited. This is the escrow problem, which stems from the Ixcoin (bitcoin) implementation: there are no balances only transactions. So in order to commit yourself to a bet with IXC as the currency (or commit to an IXC order) you need to
send IXC to some adress. Where? How the money is transfered from there as the bet finalizes? In orders involving IXC one could go around the problem (as they do in CP with the "btcpay") by declearing that IXC orders are not escrowed and the matched IXC orders are only fulfilled after the other party pays IXCs (and if he doesn't pay within certain time window the order is cancelled). That really doesn't work for bets, and it is rather clumsy even for IXC orders.
Actually, that was essentially Friction's second last proposal (i.e., CP without a specific metacoin by just stripping off CP features that need the escrow for IXC). That implementation would be then nothing but ColoredCoins. Why not then implement the ColoredCoins directly?
Yes, I see the problem with bets if IXC is not escrowed since the looser doesn't have much incentive to pay up because they don't send any funds until they know they've lost. With orders both sides generally want the order to go through at the time they submit, so it's more doable with IXC. The issues would probably be with orders which aren't filled immediately. Someone my move their IXC, but that only results in no order occurring, not someone loosing their funds.
So for bets we would need a betting proxy asset, because all assets come with escrow.
It may be true that a stripped down CP feature set could be done with ColoredCoins, but we also need to look at future growth. Even if CP is only partially implemented, it still has more potential for feature growth than ColoredCoins, so why not stick with CP.
This is from an unbiased view.
