Does it really matter what they think?
They control more than half the Black Sea coast, and access of warships via the Bosporus and Dardanelles, so if they want to boost their status with the non-US NATO powers and use their assets to help Ukraine and Western Europe to fight Russia in Crimea, then, yes, it matters a lot.
“Does it really matter what they think?”
Turkey? You bet. They control the entry to the Black Sea from the Mediterranean. And they have the largest and most capable military in the middle east (Israelis are more battle tested but Turkey would be formidable should it go to war).
The Ukraine war affects them long term maybe slightly less than it affects Ukraine as it has changed the geopolitics of the Black Sea profoundly, with Russia now occupying most of the North shore. Turkey (and its predecessor, the Ottoman Empire) have always been extremely concerned about Russia and control of the Black Sea.