The reasons for avoiding Signal (metadata leakage, mandatory phone number usage, questionable 3rd party dependencies, etc) are valid, despite how I often argue to the contrary in favor of getting as many people on Signal as possible and using it for daily communication. Talking common sense to this demographic is hard though, in the context of basic security concerns persisting year after year.
On the flipside, the phone number as identifier issue has caused apps like Kik (super popular among the gay community, despite shit security), Wickr and Wire to become popular among the non-tech demographics, which is extremely disheartening.