Is there a conflict?
Does holding something back as you polish it make it more likely that you'll create something important?
I don't think so. There's no apparent correlation.
Instead, what we see is that, all things being equal, polished is better than rushed, but the most important factor is whether or not you've actually done the work to make something remarkable/generous/challenging/useful/artful.
More time spent on that is always better than more time polishing.