I'm as surprised as the rest with the reappearance of Ryanair. It will be a good thing for Welsh passengers as competition has a downward influence on price.
But, there is always a but, lets not confuse popularity of a route with profitability of a route. Ryanair will pull the plug the moment they sense red ink. The main reason TCX withdrew from CWL was the inability to turn a profit during the Winter months on a programme (in the later years) built around the Canaries and Cyprus. Use it or lose it, as the post above said.