Trying to see how hierarchyId beats storing a "path"-style key, and it's not coming to me: a string of delimited (possibly tagged) local names, like a file path, can be searched using "LIKE" in ways that are much like XPath or LDAP queries. With prefix compression in indices, you don't pay a heavy price in Btree depth on that; and clustering works nicely, too. What am I missing, here?