The [golden rule of rebasing][golden] is that you should never do it
on public branches, so if you are using rebase as intended, that means
you are keeping private branches.  Or, to put it another way, you are
doing siloed development.  You are not sharing your intermediate work
with collaborators.  This is not good for product quality.

[Nagappan, et. al][nagappan] studied bugs in Windows Vista and found
that the best predictor of bugs is the distance on the org-chart between
the stake-holders. The bug rate is inversely related to the
amount of communication among the engineers.
Similar findings arise in other disciplines.  Keeping
private branches does not prove that developers are communicating
insufficiently, but it is a key symptom of that problem.

[Weinberg][weinberg] argues programming should be "egoless."  That
is to say, programmers should avoid linking their code with their sense of
self, as that makes it more difficult for them to find and respond
to bugs, and hence makes them less productive.  Many developers are
drawn to private branches out of sense of ego.  "I want to get the
code right before I publish it."  I sympathize with this sentiment,