> Every step towards understanding subatomic physics is a step towards cold fusion.

Is it?

You are assuming cold fusion is possible. We don't know that. It might be one more step before we finally prove it is never possible.

You are also assuming that cold fusion is something this path of research will lead us to. However this might be a misstep that isn't helpful at all because it doesn't prove anything useful about the as yet unknown physical process that cold fusion needs.

We just don't know, and cannot know at this point.