As someone who is really only concerned with High Speed Data overseas and travel frequently this is what I do.

In my case, my SO and I share one Fi account via having an extra “free” Data Only sim that allows us to share the 15GB and you can order once you have activated the primary SIM. We both have our primary T-Mobile numbers activated on our iPhone eSIMS, and the Google Fi SIM in the physical slot. While stateside we keep the Google Fi service paused, which incurs a positive bill credit of $0.66/day. And when we go overseas we unpause and use data as needed.

And since the devices are DSDS we can keep iMessage and our normal numbers as needed, and use Digits over data to make calls while not on Wi-Fi. If we need to make a call within the country I eat the cost as it’s still overall cheaper.

Rather than pay $100 for the both of us regardless if we travel that month (T-Mobile Global Plus) I pay minimum $20 (not including the $0.66 daily credit for line pause) extra for the two of us, and if we go through all 15GB overseas. Than that month alone were only responsible for $80 in service (again not including the time paused credit.

Of course this is my use situation and everyone is different, if you’re needing to make calls overseas often than another solution should be looked into.