Best use I've found for microservices is highly isolated and well-defined stateless functions which make a significant (read compute intense) change to some data and drop it somewhere else e.g. image compression.
Now you can use this microservice anywhere and just change a few params in how you call it and you have avatars, thumbnails, etc.
Now you can use this microservice anywhere and just change a few params in how you call it and you have avatars, thumbnails, etc.