Yeah, this kind of lossyness can be very bad for serious archival purposes of critical documents, because this small corruption wouldn't be self-evident nor detectable after the fact in an easy way.

Most probably its raison d'être is for non-critical stuff, such as literature, where character flips may be easily detectable during encoding and after the fact (eg. with a spell-checker) and won't possibly subvert the meaning of a whole literary work anyway.