In my experience, when a single engineering team owns the entire service, a single web app >>> cluster of microservices.

The advantage to splitting up systems is when multiple teams own part of the service and do not want to be dependent on each other for testing and deploying and signing off on features.

Although given the amount of time I spent this week to be able to send a string from my microservice to a partner teams' microservice and get a different string back, I'm not feeling microservice love today...