The lawyers refused to lie in court, because their "evidence" was just the lies and empty allegations, which would be a crime to present in court. So they were summarily dismissed, by Trump appointed judges no less.
I'm not sure what you are trying to imply. Yes, they were going to have to present evidence. They didn't have any, and that's also why they didn't actually allege fraud. And that is why the cases were thrown out.
If you're asking why anyone paid them to file unwinnable cases: So there would be lawsuits to point to, and for the (minuscule) opportunity to have a (Trump-appointed) judge create some kind of win (again to point to it).