It works for most of them, but not all. And sometimes a service originally supports it, but then changes and doesn't, which means you need to get in touch with them to fix it.
I now have a Tello eSIM ($5/mo) that I use just for the 3-4 services that don't support voip.ms. And only turn it on when I need it.
I was trying to use Tello but despite supposedly activating the esim in my supposedly supported phone (6a), it reuses to do anything. I've just switched to tossble digits which a) works for me, and b) is much cheaper!
