Asylon hasn't really gained a lot. You got Via and a could of rural regions. Most of the regions that joined you will be turned over to the new realm in due time.
Getting Via and rural regions essentially for free was a big win for Asylon. What are they going to do with their new found friends?
Hmm, we acquired 6 regions and we're probably going to hold on to 4 with 3 of them maxed out in populations. I'd say we gained a lot.
In contrast, The new colony is going to receive a city(albeit a city with good potential!) with 600 peasants and a few soon to be depopulated rogue regions.