I'm old enough to remember life before the apps. I could never figure out how to make that work. Approaching girls was stressful and hard and there was a lot of ambiguity because you'd need like some ulterior motive for talking to them and then would have to shift to dating which I never had the confidence to do. Like I'd offer to send her some class notes or something and I'd get her email. But then what?
Just walking up to a random girl and saying:
I think you look cool, wanna grab some coffee?
Would have an extremely low success rate I'm sure. Girls need to feel comfortable first, after all strangers who approach you in a public place tend to be people you'd rather not talk to. Now if you're at a bar and a friend introduces you and you have a conversation first, well that could work and it's kinda how my parents and older cousins met in the pre-app days. But if you're me in college and you're an engineering nerd and have only a handful of equally nerdy friends, those conversations are hard to come by. And that's the role the apps filled for me - the introduction.