sandeepshetty yep, this is certainly something I need to document on the wiki.
In fact most of the machine tags were a hack to add schemaless data to my MySQL-managed schema, but as I move to flat files + ad hoc indexes I might migrate some of my machine tags to “real” data — it’s not like they’re doing much good where they are at the moment.
The main benefit is easy editing — I just use my tag editing UI instead of building another UI for each different bit of data.