Human Parts will not pick up any writing that’s in another publication (they don’t want to steal from smaller pubs), so if your writing is in the Startup, it’s ineligible for Human Parts. This is definitely frustrating, having to figure out if you’re confident enough about a piece to leave it out of publications on the off-change Human Parts will see it. Because they probably won’t see it.
As to curation vs feature (and feature in a pub vs Medium feature)…
Something being curated does not mean it’s also featured. There are way more things curated than featured.
Any publication can feature your piece at the top of their pub or in their email, etc, but there is a separate meaning of “feature” on Medium. If Medium itself features a piece (usually pieces from their own publications, but they sometimes feature other pieces while leaving them in their old pubs), they may put it at the top of the Medium front page and give it a very wide audience in other ways.
Medium has featured quite a few of my pieces now, and they have been tweeted/shared on FB by the official Medium account. This obviously gives them a huge boost.
Let’s celebrate every win, big or small!