The reason people make the group or event is because when you invite everyone they get a notification and a lot more people see it rather than a status update (that maybe <10% of your friends see). So maybe creating an event or group then linking to givemeyournumbers.com/john_smith
Many said this isn't wide-used anymore. But as a high school student, I still get invited to those groups/events frequently, and people said they've been waiting for something like this for a long time. So there is still a big market here.
Glad I could contribute my little bit to make this process a lot faster. Well worth making this as my 5-hour side project.