Push a button, get people to hang out with you.
Problem is that people meet up using chat, that’s the core thing you have to be better than. Better, faster, simpler or easier than WhatsApp/Messenger/iMessage/SMS/FB Events/Instagram/Snapchat. Those things have extreme network effects and you probably will not dislodge them, I would aim somewhere else.
This exact app is detailed in one of NFX’s write ups as the “wrong” approach.
If you still want to try getting users, throw it on Product Hunt and see if it takes. The only momentarily successful version of this was Down to Lunch - and only because they harvested your entire contacts list and then messaged every single person at once to get them using the app. They’re gone now. It was simply easier to group chat your friends “yo movies?”.