The obvious answer to this is that if the people don't even care to try out another app for keeping in touch, they're not worth it, since you even have good reasons for not using WhatsApp I suppose. Dont you think you would be a guy interesting enough to justify hitting an "install" button in some app store? Its about self esteem and not about them in my opinion. People eventually will get in touch, maybe after you met them two or three times more by chance.
Hiros platz im Fediverse