I made around 11000 km with a belt on a cargo bike before selling it and the belt on the current one is at ~6000km. Belts are amazing, especially when it comes to maintenance.
But I would still avoid going with a belt on a tour anywhere that’s remote - not because the belt itself might break, but the hub (as for this guy), or a sprocket or anything that is uncommon, but required when riding a belt.
I do carry a spare on tours