gzip and tar+gzip aren't good options for application data compared to zip.

zip is used for Java jar files, OpenOffice documents and other cases.

The benefit is that individual files in the archive can be acces individually. A tgz file is a stream which can (without extra trickery) only be extracted from begin to end with no seeking to a specific record and no way to easily replace a single file without rewriting everything.

tgz is good enough for distributing packages which are supposed to be extracted at once (a software distribution)

gzip is not an archive container. You're thinking of .tar.gz which is a "tape archive" format which is compressed using gzip. Zip is by itself both a compression and an archive format, and is what documents like epub or docx use