Makes sense, easier is better. To me the big benefit is lower fees but being able to pay fees in XCP would be valuable as well.
If this is implemented I do think that an option should still exist for users to send transactions directly, paying a higher fee in BTC to circumvent having their transactions aggregated. Some people might feel that running transactions through a server introduces counterparty risk, similar to masternodes for Dash. Sending transactions to be aggregated for a lower fee should be the default option though.
Also maybe this goes without saying but rights to run an MCAT could be a token or tokens with each server associated with a wallet address. In any case there should be some easy way to transfer rights after they are issued.