Rankings plays no significant role for my app, although it does affect downloads a bit. My app has been in the top 10 for a while, but also around 30-40 or so. It was never featured by Apple.

My app doesn't target people who just browse the app store and look for new stuff. It requires people with domain knowledge to actively seek a solution (I offer). So, before people get to know my app, they usually find themselves to get to know about the domain.

As an example: Before you download an app for vegans, you read about veganism first. There is no point in downloading an app for vegans otherwise. It's similar with my app (different domain though). But once your vegan app is somewhat popular in vegan communities, you depend less on rankings and more on SEO and word of mouth.

Of course, being featured by a vegan magazine would do a lot for you, probably more than being #1 in the app store or being featured by Apple (in terms of customer loyalty).