I'm unsure why the distinction matters that was brought up in the post. It really comes down to what do you need to support, and how much weight you can swing.

Are you a small time supplier, and want a major retailer to integrate with you over API? good luck. The decision really isn't yours, if you want to get paid, you integrate.

I think the reality is that most developers would rather use an JSON API instead of EDI. EDI is sometimes talked about as just X12 / EDIFACT, but the protocol is baked in as well, which causes more headache (who wants to build an EDI stack?). X12 was built during a time where VANs probably connectivity, and caused per character, so everything was positional based and inferred. Modern APIs are descriptive, and easier to use.

(fd: I work for Orderful, a company that provides an API and then translates it to EDI so you can easily work with any trading partner)