The idea was that Sweden and Finland would enter NATO togheter. Finland bordering Russia is by far the biggest argument for them and Sweden also semi borders Russia by ocean access.
This discussion was brought up early in the war when it was not clear how strong Russia was.
For me I don’t see the point in joining anymore but was a bigger consideration early.
Though exiting the deal when Finland already joined would put a dent in our relations. Sad we will lose our decades of neutrality because of one dictator biting of more then they can chew, but so be it.