Skyscanner had a great service when it included Ryanair flights. Ryanair lost nothing, since if you selected their flight, it took you to the Ryanair website with the booking details all ready to process.
I quite often used it for finding somewhere to take a short cheap break to where I knew my travel availability but had nothing specific in mind, and quite often Ryanair were the people who got my money. Now that I have to trawl through the inefficient Ryanair site to look for a non specific flight, everyone else on Skyscanner is more likely to get my business as I don't have the time or inclination to spend half a day on an amateur and unhelpful website.
Cutting off their nose to spite their face methinks.