There's not much riveting gameplay at all, it's a management/collection game through and through. Like a more weebish, repetitive pokemon. But it can be quite comfy if you're into the planning aspect, and for me it's been satisfying training up my fleet to the point where all the maps and battles I used to struggle with are ezpz. It might look intimidating with all the guides and hidden mechanics, but it's very slow-paced. You even gain resources from not logging in.
Your experience with the game depends on the goals you set for yourself (do you want to collect all the ships? Complete every event on hard mode? Complete every quest in the game?) But if you want to take it easy, then it's a nice, casual game to unwind and play on the side.