If the software makes money because it's expected to work reliably, every edge case matters. Web games aren't exempt from engineering challenges. In fact, the more trivial the problem seems on the surface, the more likely it is to have edge cases.
Bugs are always prioritized based on how big of a deal it is for the customer. They don't like to wait and they rarely give second chances.
AI doesn't fit into any dev workflow except greenfield or analysis. Everything else needs a lot of close human attention and human discussion. AI doesn't read minds.