if NATO was a normal economic bloc, then yes. But it is a mutual defense block. Turkey is pretty much forced to defend Finland, or any other members of NATO, if they are attacked. Turkey, as well as any other countries in NATO, have to be OK with sending their weapons, ammunition, and most importantly, soldiers to defend Finland, as well as other new applicants and current members.

I hate the fact that Turkey and Hungary is holding up the process, but it is a process I wholeheartedly agree to.