I reckon it's probably not that much. There has to be tens of thousands of customers worldwide that are using their shitty app.

Forks and stars on the original repo numbered only in the hundreds.

Cloud services and API gateways usually charge once you get into the millions of requests. Amazon API Gateway doesn't even charge for having the APIs active - only for the requests that are received and the data transferred out.

I'm finding it very difficult to believe a few hundred HA users even came close to putting a dent in their cloud bill.