Some things that keep me away from SimpleX:

- No multi-device support.

- No group calls.

- Establishing a contact requires sharing a large link or QR code, which is often inconvenient.

- Message queues drop messages if not retrieved within a relatively short period. Last time I checked, it was 21 days, which is shorter than some of my off-grid vacations.

- I couldn't find clear information on who runs the message queues, so I have to assume most are controlled by a single organization. This makes it effectively a centralized service with respect to privacy and resilience.

- Funded almost entirely by venture capital, making its longevity questionable, and the likelihood of future exploitation relatively high. I'm not comfortable depending on such a service to keep in touch with people.

SimpleX is cool, but it has VC investors, so a lot of people won't trust it long-term (for exactly the same reasons we're talking about replacing WhatsApp now).

When I last looked at this it had severe battery drain issues on Android, to where users with only one contact and just a handful of messages were experiencing it. Appears that pinned issue is still open and unresolved.

Otherwise it seemed like the most promising alternative I've seen that satisfied various requirements.

I've used SimpleX for seeral years. I do like the concept, and I have supported the project, but in my opinion it suffers from two weaknesses/lacks:

1. It cannot synchronize chats across several devices, so you need a separat “account” for each device. This can, to some extend, be mitigated by creating a group for each contact you communicate with, and then add all their and your accounts to that group.

2. Message propagation is somewhat unreliable: If you use the method described in (1), some accounts may not receive a given message.

But yes, you needn't disclose your phone number in order to create an account/profile on SimpleX.