I like the concept, hate the execution. That said, sheet pan fajitas are a lifesaver if you’re serving more than like 2 people. Same for like the pizzas and other things where you’re maybe splitting up two similar things.
The rest of these… possibly a good idea if you’re using pre-prepped ingredients. That said, I don’t know where to get pre-made brownie batter in the same way that they sell premade cookie dough.