I think when you look at a messenger app the big things you want to look at are:
- How many of your friends/famlily use it or would be willing to switch.
- Privacy and security provided by the app.
There are lots of very secure / private messaging apps out there that don't require a phone number (e.g. Session, SimpleX) but there are not a lot of users, and good luck convincing your friends and family members to use them.
In my opinion most people have to look at tradeoffs. For example, I use Whatsapp not because I want to but because a lot of my local and international contacts use it and its more secure and private than using something like SMS. Again, I'm not happy that I'm using it but that is the tradeoff.
I also use Signal and had a number of people switched over because it allowed encrypted communications between Signal users but also allowed SMS communications with non-Signal users. I could use that as a selling point for people who contacts who "didn't want another app on their phone". Encrypted communications with audio and video calling for Signal users plus SMS support all in one.
Now Signal is taking away SMS support which I think is going to significantly reduce their user base in North America where SMS is still very well used.