Yes it is.
And yes, I do have Signal installed, and there are only 2 people who talk to me through it (one being my partner).
Phone carriers got too greedy charging for every single SMS message and phone call, WhatsApp took over when smartphones became popular.
I'd much rather use Signal but that's not realistic.
IIRC South Korea used to be fully depedent on a horrendous AcriveX applet running only in Internet Explorer for all their online services, yet they eventually managed to get rid of it. It should be possible here as well.