Slava Murygin has some information on the DBCC UPDATEUSAGE command:
As you can see, UPDATEUSAGE found three problems with that table, while was running in “ESTIMATEONLY” mode. When it run in “Fix” mode it also found and fixed only three problems. The number of rows was still left unfixed.
I think it’s fair to say that this is a relatively uncommonly-used DBCC command, but can definitely be useful in a subset of circumstances.