Where you get in trouble with the heel is around the curves: The heel of the spike touches the track more and you’ll end up racing like a distance runner (more GCT). You can even run 60 or 100 even in long distance spikes without much effect, because you are (or you should be) sprinting on your forefoot. The problem with mid/distance spikes is greater for the 400 than the 200 because in the 200 you’re accelerating and not going as fast for much of the curve.
You can do training in distance spikes, but if performance really matters, I’d stick to racing 200 and 400 in real sprint spikes.