* A recipe for typo-based-bugs.
* Makes the code difficult to read if there are subtle differences, since they get lost among the identical repeated parts.
* Indicates that there is (probably, not necessarily) a meaningful abstraction you could have used.
I would say it's technical debt, that needs to be paid. Perhaps not immediately, but don't let it pile up.
So: Don't "let it go"; rather, pursue it somewhat more flexibly.
PS - There is more to clean code than less duplication...