This was often a food for kids (<10yo) in Utah, USA, and other rocky mountain states.
I've eaten this often, in the Southeast US.
There are a lot of things that go great with peanut butter and bread if you are open to it besides jam or honey - cheese, butter(toast), hazelnut spread, fresh fruit like bananas. Running out of groceries and living 20 miles from the nearest store leads one down this path of trying whatever is in the refrigerator/pantry.
It was pretty normal for me in NSW. I used to add sliced banana sometimes as well.
I grew up eating this (and odder combinations) in new england.
Second Aussie checking in. Lived in every capital along the east coast, bar Hobart.
Also swear I've never heard of this in Australia :\ Make of that what you will.
Very common in rural or frontier USA
Definitely a thing growing up in central Victoria in the 80s/90s.