As I recall, they have a much lower rate of tone deafness than the rest of the world, and a higher number of people with perfect pitch. Similarly, the mutation that makes Cilantro taste like soap is much more rare in places where it is a common part of the diet.
Anyhow, you left out how "Lingua Franca" literally means "(the) French language", as they were the dominant force for a time. It remained the language for diplomacy well into the era of British dominance.
Note that most of the world uses the Latin alphabet, while the Chinese lexigraphy is an absurdity. Also, that analytic languages are mostly limited to China and its neighbors to the Southeast, and they suck. Synthetic languages, like almost all the rest, are far more flexible, expressive, and comprehensible. Plus, the rate of falling tones ending in 'ng', 'o', or 'eu' is much lower. I hate hate hate those sounds.
I just don't think it's likely that a Chinese language (Mandarin is dominant, they've suppressed Cantonese and the costal languages) will ever be the Lingua Franca. Look at the rate at which English adopted Japanese loanwords vs Chinese. Everyone knows what karaoke is, but what Chinese loanwords do we have? Some martial arts and Feng Sui?