Did you miss that this is oriented around serverless? It doesn’t mean their application is tiny, it just means they can scale down a long way. Which, given that they are using serverless, is unsurprising.
Sure, if you are talking about dedicated EC2 instances or something, then a $150 “production” instance is tiny. But that’s not the situation here. $150 for developer load on serverless doesn’t correspond to $150 for a full production service.