Probably signal occupies a far greater mind share than it's userbase actually warrants. If they say they have 10000 DAUs, more people will write it off as worthless rather than he interested in trying it.
I have 8 contacts on Telegram, one(!) conversation. Meanwhile everyone from family and friends is at Telegram now and used to be on WhatsApp.
I wish Signal all the best: it is totally impressive, they got their incentives aligned totally unlike WhatsApp and to a larger degree than Telegram I think.
Personally I'm rooting for Matrix, but for now, based on my limited understanding Signal seems to hit the sweet spot where "kind of easy to use" overlaps to a large degree with "trustworthy".
Also, should anyone get banned from mainstream messenger because they live in the wrong country or have the wrong opinions they can run their own.
This is a huge step forward :-)