In most cases, it is convenient to have some human interaction with a web (micro-)service, no matter how small it is. A traditional approach would be to create an HTTP interface, where user requests will be dispatched and HTML/CSS pages must be served. This approach is indeed very traditional for a web site, but not really convenient for a web service, which is not intended to be good looking, 24×7 up and running and UX-optimized. Instead, talking to a web service in a chat-bot mode would be much more convenient, both for a user and web service developer.