That’s a good debate to have. I settled on JSON due to its readability and ubiquity in web APIs. It’s something people all the way down and up the stack are very familiar with these days.
True, folks are very familiar with JSON, but it does have problems, and the best time to pick the best solution is before one has to deprecate a lesser solution. Computing is built atop a pile of decisions which made sense at the time and cannot be changed now due to compatibility (spaces in Makefiles, anyone?): there is no time like the present to simply choose to do the most correct thing.
'But folks won't use it!' Well, they might not. But if one gives folks a choice between the capability they need using an unfamiliar technology and not having the capability at all, they will learn the unfamiliar tech.
