I was just lucky. That was a funny roll on a character I’m not focusing on.
I’m pretty confident it’s generally not worth doing it on more than one character. Some of the per-stage rewards are character bound, but you can only receive them once per team. It’s weird. Only situation where I can see you doing an alt is something like this:
You have a main that’s really strong but basically maxed out in attribute points. It doesn’t need more. You have an alt that needs attribute points but isn’t very good at leveling your monsters. You get some basic monsters on the alt and just clear stage 1-5 every day for the 1k attribute points. Then you try to push as far as possible on the main and actually try to clear everything else.