Hi, I didn’t forget about background processing, omitted them from the post because as you pointed out, latency is not much of an issue there so cold start times don’t really matter in most of these background processing scenarios.
I’m not saying API Gateway + Lambda is a bad product. I have used it a bunch, probably more than most, if you check out my series on our migration work from a monolithic backend to serverless you’ll see that API Gateway featured heavily there.
But let me also just say that, there are consumers of your API (other APIs, ETL processes, mobile or web apps and what not), and there are users of your system (humans!). When I say “making user happy”, I meant entirely the latter.