Incremental rewrite isn’t a rewrite at all. It is the better choice though. It is worth noting that refactoring and improving an area of the code without a need to change it or build new features on it is also wasteful.
Calling incremental improvement a form of rewrite gives it a bad name :)
I’d argue that rewrites that are a second system that (hopefully) eventually get deployed once the features exceed current system is not incremental at all, but is instead Big Bang.
Even if the features of second system are built incrementally, if the business aren’t using it until it is finished then it is Big Bang.
If the plan is to change all the parts one by one until done, it's a rewrite. If the parts are changed one by one for independent reasons, it's just code evolution.