Websockets are cool. They are the modern sibling of http in that they run over tcp, but websockets offer a lot more, most notably full duplex (i.e. data can be sent in both directions) and realtime delivery of messages.
Those two features enable the creation of web pages that update dynamically as soon as new data is available on the server. No need to reload the web page in the user’s browser.
I have been struggling with how to get websockets integrated with MQTT on my Synology DS1515+ NAS, but in the end it turned out to be pretty easy!