You can't compare the amount of work needed by an indie developer between creating content by hand and using a prompt, they are not comparable, one is vastly simpler than the other.
No matter how much you want to justify your workflow, it is much, much simpler than doing it without AI, if it weren't this way, you wouldn't even be considering it.
You have people who don't care how you made your game and they don't care if you used AI or not. They only care about the result and a song or a nice image created by AI will be more eye-catching than what you can do in a traditional way.
But there are other people who don't want to consume products created with the help of AI.
If you want to use AI, use it, you know better than anyone what is best for you in the process of creating your game, but respect your consumers by being honest, inform them if you used AI and let them decide if they want to consume that type of product or not.