In my experience [1], these global insurances can either have limited coverage amounts, limited coverage duration, or will recalculate your premium every year as if you just joined. Regular health insurance would put you in a bucket and use the bucket's general risk to price everyone's insurance, leading to steadier premiums. They often offer little to no coverage in the US and Canada.

These are great for getting temporary coverage while you wait for a residence permit, but there are few use cases for them outside of that. In Germany, I actively try to steer people away from them.

[1] I wrote this: https://allaboutberlin.com/guides/german-health-insurance