A tiny fraction of their users paying upfront (remember opportunity cost of money) is hardly going to doom them to insolvency.
Look at this way - investors give money to a company now to receive money later. They risk capital now in exchange for future rewards. Lifetime subscribers pay a large fixed amount now to receive free service later. Same thing.
I was surprised to see the artifacts when I looked at the full-sized image - even though I shouldn't've been cos AI gonna AI.
It's really cool that it understands that it should look blocky, but not that the blocks should be aligned on a grid. It's accidentally been way more creative with the brief than if it'd emulated pixel art better.