On my distributed monitoring set up I am using Host Tags extensively.
I have around 2000 Tags that are controlling many rules and views. And having them predefined helps putting asset numbers and serial numbers on hosts. Tags can also be used to define locations, customers, rooms, contacts, warranties, system functions etc…
We even wrote software that synchronizes the host tags using the REST API of Checkmk with our ticketing system. Additionally, we use the tags together with dynamic host information from agents and snmp to automatically create offline documentations of hosts with a template.
Having the Tags stripped away would leave my setup totally unusuable. If the Tags are removed in future versions, I won’t update.