Obviously, you aren't too concerned about 1 (the cost to you), because
you're willing to do that work. However, if I were Junio, I wouldn't
be willing to "spend" costs 2 and 3 on a patch that didn't either fix
a problem or provide a new feature.
For any decent codebase there is a need to keep the code clean.
Being part of the linux-kernel community we see clean-up patches
each day and a lot are applied.
Even spelling errors in comments are sometimes applied.
Do not underestimate the value of a clean codebase.
Sam