Not quite. xattrs are not indexed, so if you want efficient retrieval by xattr tags you have to build/maintain your own inverted index. xattrs are good if you have a file that you want to store metadata about, but not so good if you want to use that metadata for discovery (at least in my experience, maybe I'm missing something, but I've implemented a remote file syncing system using xattrs and I never came across a tool in the unix arsenal beyond find + getfattr which is painfully slow).
I made heavy use of OpenMeta (that was a community effort on OSX, before Apple introduced something very similar), that placed tags in xattrs. It is great! Retrieving never caused any issues or slowdowns.
