I've met several partners off the internet through means where images were not involved, but it was clearly geared towards dating still (mainly reddit, if you would believe it). Some like to get the images out of the way early, others talk for weeks before that becomes an issue. There's still some that then drop out (I'm not the most attractive lad to ever be a lad, plus preferences exist, as you say) but others worked out great.

My strengths don't lie in my style or looks, so dating apps are basically useless to me, yet I have no trouble in attracting partners in circumstances where my personality is a bit more in focus.

I think there's a space for apps like those for sure. Since there's plenty where you can go purely or predominantly by looks, no one has to go for an app where that is the case.