Yeah... for us, a big part of using Whatsapp are the groups we set up for our family across international boundaries. It created simple habits for relatively non-technical users - so they use it for all communication. (voice and text)
For me... I have a dual SIM phone with Google Fi and DNA (local cell service provider). I regularly use normal cell services (call and text) on two numbers, WhatsApp, Discord, Slack, Zoom (meetings and voip phone), Vonage Extensions, and email.
Regarding Google Fi (
https://fi.google.com/about)... best thing since sliced bread. It is fkn awesome for a person travelling. My US number works the same anywhere without worrying about exorbitant costs. I cannot say enough good stuff about it.