Honestly, I would say the rewards are quite decent if you want to exchange your Energy dust. The shop has a periodic reset where you can exchange all three types of dust and get new equipment or items for your characters. All the items there are to help you invest in your character and get a boost in damage output. It's important to remember that the core of this game is to invest in your characters consistently and progress through the content. Monsters that seem like a hard wall at first will become a cakewalk once your character is invested enough. Games like Tower of Fantasy, Honkai Impact, or Genshin Impact require players to invest time in their accounts to go through challenging content in the end game. Personally, I don't spend much time on the game, but whenever I get an opportunity to stack up some resources, I always press the collect option and sneak them quietly into my inventory.