We have never come across one that is as easy to use as Signal and has no problems with encryption, either that it can have its encryption turned off, it breaks easily or that it makes dubious claims with few-no audits to back them up.

Plus the common person enjoys the fun features of Signal or other easy messengers, most decentralised messages do not have these features, are indefinitely working on them or make them not as easy to use, leading to most being uninterested in those messengers.

We have tried most if not all of them, than most and they are definitely lacking as much as we wish they were not. Decentralised encrypted (or partially encrypted) messengers always seem to have problems whether it's with their encryption, moderation tools, connectivity or the lack of other features.