For the latest airline to be the number 6 player on a route I agree this is maybe a surprising move.
In the bigger picture I think this kind of thing is rather good - it tests the depth of the market and will make everyone aware that even London to the Spanish beaches is not a supply of unlimites profitable revenue. Should wake everyone out of their stupor and remind chief commercial officers of the importance of product innovation - namely have something unique to sell (eg an unserved route) rather than the same as everyone else