every other app puts a person in front of you and asks whether you want to know them. that is a heavy question to answer about a stranger, and it is the wrong one.
Let’s asks something much easier: do you want to do this thing, on this day, near here. saying yes to a bike ride costs nothing. you find out about the people on the ride.
that is the whole difference, and everything else in the product follows from it — the feed is made of sentences, not faces, and the chat exists to get four people to the same place at the same time, then gets out of the way.