It's small-scale, has high barriers to entry, and entirely user-directed. In other words, the exact opposite of what makes money in profit-driven social networking. And that's exactly why group chats are so great.
Group chat has been a thing since the late 90s and remains superior in my mind as well. It often seems like the real problem some of these apps are trying to solve is that there's no good way to monetize group chat.
"My people" are people who once were in that sort of temporal and geographic bubble, but are not necessarily local top me any more.
Some of the most important people in my life are spread around the globe, and we only get together in person once a year or maybe even once a decade (more of those lately, given global health stuff in the last half decade).
I bet almost everybody who's ever been to Burningman more than two or three times has the same sort of geographically distributed friend circles. Same as anybody who regularly goes to a specific conference (I have friends I originally met when I was going to The Perl Conference in the late 90's), or festival (I have a close cicrle of friend who mostly live 1000km away that I met/meet every year at a music festival).