Suppose you have set up everything to get you going with a single route. Now, adding another route/handler is just deploying another function. And you deal with

Suppose you have set up everything to get you going with a single route. Now, adding another route/handler is just deploying another function. And you deal with everything at this function level and never the entire "monolith". You get all the advantages of breaking free from a "monolith", independent iteration, scale, federated management. Consider a big team which writes 100s of routes/handlers, then you can just federate the ownership easily. Not very great for a solo-dev kind of projects, I agree.