These are costumes. The only exception being taunts ( same as buying emotes ) and the Neptunia pack that adds an extra character. The Awakened character pack i think gives you a variant of a couple of characters, essentially an "evil ryu" version of a couple of characters.
Since this is a game that already gives you literally hundreds of costumes and customization options and has literally dozens of characters, i think this is quite fine. Also, Peach Beach Splash is a legit good game. It is absolutely caked in Over the top fanservice, make no mistake about it. But it is a well made, good game.
Hell, the game has a card pack system for leveling and power up and yet the DLC does not sell you those, That's entirely in-game. That alone already makes this quite fine.
I know, i know "DLC is the devil" and all that. i too hate Lootboxes... but let's try to focus the criticism to where it is an actual problem.