When the $2 coin happened, lots of people called it the dubloonie (in most canadian minds, what pirates used). Eventually though, it settled on "twonie".
This sort of cultural change is dynamic, and very influenced by things happening during the transition.
No history book, no movie, etc accurately captures the "word on the street", what the average joe thought at the time.
So, who knows why? Living through the above changes, I simply noticed more and more people settling on one term or another, and eventually.. it just was.
It was a great show, pity it's long gone. Certainly better than shitty entertainment we got now - and at the same time not as pretentious as "Wielka gra".
"It costs how much? 500 Euro?! That's 1000 guilders!!"
"It costs how much? 500 Euro?! That's 1,000,000 Lire!!"
the conversion was 2002, so only little more than 20 years ago, people 40 and over have grown up "in local money".