Volatility.  If the majority of BTC you hold is in cold storage and the price starts plummeting it takes a considerable amount of time to get your BTC out of cold storage and onto an exchange.  Price in USD could be down another 20% by the time you actually move your coins.

If you're new, try mining on one of the profit switching pools.  I use middlecoin as a failover, you won't make the most on it but it seems to be the most stable.

I would expect an exchange to start listing COYE relatively soon.  Huge hashrate and it would be stupid for any exchange to just leave money on the table.

I registered to post the same thing.  Luckily I cashed out this morning, but I think I still have around 50k COYE in that wallet...