I would say that JSX is popular precisely because the cost of teaching it is low, which in turn is because of its similarity to other commonly used notation (HT

I would say that JSX is popular precisely because the cost of teaching it is low, which in turn is because of its similarity to other commonly used notation (HTML / XML). Of course it's got its fair share of dumb gotchas, but I found it far easier to learn than, say, any of the myriad Rails DSLs.