LISA is scientifically valuable even if it fails to detect supermassive black hole mergers because it will capture gravitational waves from millions of stellar-mass binary objects.

“I want to make sure that y'all know that Lisa would still be great even it would not detect any of the massive black holes. And that is because as soon as as Lisa turns on, um you're going to be able to detect all of the uh the individual black hole b stellar mass black hole binaries”