And plenty need to serve non-UTF8 data, such as images, or documents with a content encoding (like the GP was trying to). Sure, "JSON toys" is a bit hyperbolic, but "HTTP service that can transfer media" describes some double-digit percentage of all web services. API Gateway may fully support many use cases, but in my mind it's a toy until it supports this major one.

(Note that it's not like API Gateway claims up front "JSON only!" or some such. Outbound binary data just silently gets garbled and the only mention of this limitation is buried in various threads on the forums.)