The game is pretty flawed and a bit barebones compared to other games on Nutaku whose premium Gacha girls actually progresses the game and makes things easier or challenging
Look at Kamihime, Aigis, Flower Knight,
The,re is no incentive to spend real money on this game once you get a handful of girls to provide money to buy equipment and affection and you will be at a higher level to get stamina to progress which is a bit slow
If you want to collect girls for the sake of collection the game for you
Otherwise those who prefer action or another gameplay over click and grind low drops - I got played the game for 6 months and just lost interest