fwiw, malted oats do have diastatic power, typically guaranteed 25 minimum, not quite self-converting, while rolled/flaked/steamed oats have zero diastatic power. I use one, the other, and sometimes both, depending on the recipe and what I have on hand. Other than Golden Naked Oats, which has a distinctly different character, I've not found a practical difference between malted vs flaked oats in the finished beers.
The one thing to keep in mind is it takes a skinny mill gap to crush oat malt. While I typically run my barley mill at .032" gap for barley malt, my oat/wheat/rye mill is set for .020"...
Cheers!