Perhaps it's more important to have Turkey in NATO than Sweden and Finland, but I honestly don't know. I hear Finland has a strong army and it's useful to have all of the Baltic Sea countries in NATO.
Turkey's location is incredibly important strategically. They control access to the Black Sea.
Turkey is second-largest based on manpower, right? Time to update that ranking soon: Turkey 775,000 vs Finland 937,000 military personnel available
Turkey has NATO's second-largest army, for one thing.