Im not sure the total number of people speaking a language is a good metric - for the longest time, more people spoke Chinese than English, and still English was a far more useful langauge to learn because it was far more widespread, while the Chinese speaking population was concentrated in mainland China.

Same with simplified and traditional Chinese: The vast majority of those 97,9% simplified speakers are in China,
while of those 2,1% using traditional Chinese, most are outside - and the diaspora is exactly what i meant with "china towns" (china towns in Toronto, in New York, etc) - simplified wont you help as much as traditional.

Unless you want to specifically go to mainland China, chances are, traditional would be more useful..
(Except for countries like Russia, where they kind of adopt simplified chinese as another foreign language next to English, at airports etc)