The main issue with WhatsApp you're locked to a single provider and their service (unless SMS which works across different carriers), as well as their privacy practices. In a way this is similar to people moving away from email to proprietary messaging systems instead - while you gain security and functionality benefits, you lose in terms of choice and compatibility. Sadly alternatives haven't really gained traction.
I agree, I don't like whatsapp. Though I do like it more than SMS.
One of the things I like about it is group messaging. The seamless images/files, the encryptuon...
And I don't think most mainstream users feel this as a lockin. After all whatever phone they can buy they can install whatsapp on it (and soon even import their hitory!).
Personally I prefer Matrix. Not a fan of Signal either due to the ban on 3rd party apps.
Yeah I personally use Matrix myself, I run a selfhosted instance for internal family use. They're the only people actually willing to use it - everyone else is on WhatsApp and similar services.
