I don't have the provision in front of me, so I'll be answering purely on my memory of the provision that you refer to, which is an existing provision of the Criminal Code.
That provision was put in for the purposes of ensuring that a person would not have a bogus acquittal or a bogus conviction in a foreign country and then say, if they were arrested in Canada, “Well, I've already been tried and I've been acquitted” or “I've already been tried and I was convicted and I got a small fine, so you cannot try me again”.