You still have to cover the extended medical care in Canada and they are often bigger than the initial hospital stay in the most expensive cases in either country (years-long therapy, chronic injuries, etc.)

The tortable aspect (compensation for causing personal injury) must also be covered.

Probably the liability is also different? You're much more likely to be liable for some things in the US compared to other places.

In my part of Europe, if someone breaks something while making normal use of your trampoline that would be considered an accident. You would only be liable if you had grossly neglected maintenance on the thing, knew that (or would reasonably be expected to know that), and they can prove that this has caused the injury.

Possibly. Also in my country (in EU), the home insurance doesn't cover your liability for an accident like this. That would be another type of insurance you buy extra.

Possibly. Health insurance companies may want to sue the home owner insurance company to try and recoup costs.