I think because simpleX is more open source, self-hosted, and maybe slightly more anonymous. Not sure how the usability trades off for that if at all because I haven’t used it (I mainly use signal and discord)

It also doesn’t seem to be a mass migration by any means, just that simpleX is a bit better if you are super hardcore about your privacy.

Even if your monero wallet or account or whatever is firmly linked to your real identity?