Zip is terrible as a local files system, unless you consider read only (randomly, and not many files). Writing/append to a file requires some form of garbage or

Zip is terrible as a local files system, unless you consider read only (randomly, and not many files). Writing/append to a file requires some form of garbage organization/compaction - which requires rewrite of the entire CEN. Unlike the regular files/entries, CEN doesn't have a checksum, so corruption there is pretty bad. Each file being compressed individually means low compression rates, the deflate overhead might be acceptable for slow mediums (although in that case the memory overhead would be non-trivial).