I had a the last skyroam device when it was 3G. It didn’t work out, even though it said unlimited, the acceptable use policy limited use to something ridiculously low like 500mb/day (I’m not suggesting this is still the case).

the other issue is that cell data is routed through the home country of the underlying carrier. For FI it was T-Mobile in the US, for keepgo it was the UK, and for skyroam it was China. It made for terrible ping times outside of Asia.