[Grampa]

Yes, that's the same idea, but with the ability to choose different outbound trunks based on the dialplan. The one disadvantage of using a different SIM card for each country, compared to a single international SIM card, is that you would need to redirect the inbound PBXes trunk whenever you changed cards. This would be invisible to callers, but it means finding an internet connection every time you change location, which is something of a pain.