The purchase only options have never been game changers. They offer some utility occasionally but have never been the make or break point.

The other purchsse just simply speed things up. You can grind out hundreds of battles for Dark Lillith and Lucifer or pay $200 to get them without the work. The $20 event packs just cut out a bunch of grinding.

And of course there's the ever present ironite purchases that can be used to speed up most aspects of the game.

This game is freemium to a T.