I think A300BOY is right. J2 have tried to play the yield management game and have reduced frequencies on a number of routes for S10. This has opened the door for RYR & others.
The airport wants growth and this should help. The catchment area is large enough to handle both airlines and 14 routes with 2 aircraft is not likely to create a serious dent in the Jet2 operation where the 2 compete. (There doesn't seem to have a been any fallout on BCN/GRO or ALC so far.)