Interesting, in the US they often do that too but I’ve personally never filled it because insurance doesn’t cover over the counter medications. So I’d have to pay cash for it.
(It is worthwhile to note, because Americans don't realize this, but not all medicines that a doctor prescribes for you is free, although the overwhelming majority will be.)
It depends on the insurance. I have pretty crap insurance and didn't expect them to cover a prescription for Omeprazole (aka Prilosec) since it's available OTC, but to my surprise they did.