I swear I'm not a Luddite, but I just don't see the advantage of these apps versus going out and meeting new people, no matter whether it's at a coffee shop, on the street, in a park, at a conference or at a bar. Investing your time in a few five minute conversations has got to be a better way to meet interesting new people than broadcasting your interests in a 100-yard radius and having an algorithm match you to peo…
If your goal is to meet new people that might become friends or repeat acquaintances, you probably don't just start talking to random people on the street. You could, but most of them won't be interested, or you won't be able to find substantial common ground in the few minutes that you have to make a connection. Conversations will be short and awkward, as you fumble to find an topic that you and your target can both be interested in. At least, that's been my experience as a shy, fairly introverted guy - if you're a smooth, sociable person with a lot of experience interacting with people, you might have more success. If you do, more power to you. You probably don't need ambient location apps!
However, if you want to minimize both time spent and awkwardness, it's a good idea to put yourself in some kind of context where anyone you meet will have a shared experience or interest that you can use to break the ice. If you go to a sports bar during a football game, most people there will have some interest in the sport in question. If you go to a conference, most of the people there will be there because they're interested in the topic of the conference. If you go to a coffee shop, you're either there to drink coffee, or you're doing something while drinking coffee that could be the subject of a conversation. These are all stronger shared contexts than incidental contexts like "random person I saw on the street" or "guy I stood behind in the grocery store checkout line". I don't know about you, but when random people in the checkout line start talking to me about how long the line is, I get a little creeped out.
"Ambient location" apps are just a high-tech extension of that idea of shared context. You get an easy way to find people that a) have some kind of shared interest with you, determined by the app's algorithm and b) have explicitly decided to look for social contact by installing the app and setting up a profile. It's just a way to opt-in to social situations that might have otherwise gone unexplored because you never encountered the person in a context that gave you cause to talk to them.