You'd have to convince everyone to switch to it and most Americans are going to have the reaction of: "Why would I want another fucking app that I have to make another damn account for when I have something that does pretty much what I want built in"
Activity groups will usually use some other service for member messaging (ex: my D&D group uses Discord for campaign discussion even though we all have eachothers phone numbers, a outdoor activity groups like a hiking group may use a facebook page, etc.)