Howdy waikatodhb,
I would love to help clarify this. Multisite licenses are intended for multisites, so that is the one most people use. It gives you automatic updates, and allows you to manage the license from the Network Admin side.
However, any license will work on a multisite. If you are running a particularly small multisite, it might be a better deal to purchase one of the cheaper licenses. The only caveat is that only the multisite license provides automatic updates. More info here:
https://theeventscalendar.com/knowledgebase/multisite-license/
Does that all make sense? Will that work for you? Please let me know.
Cheers!
– Brook