I’ll take JSON over text any day.

Email parsing can break in so many subtle and/or obscure ways that I have trouble putting any confidence in the parsing code I’ve written… it’s quite frustrating, especially since there aren’t well tested mail parsing libraries for every language/platform to fall back on.

On the other hand, JSON parsing errors are reasonably bounded and there’s well-tested highly optimized libraries for it for practically every supported platform and language. No it’s not perfect or even well suited for the task, but it’s still an improvement.