Artifacts may contain large number of small files. In this case would be useful having the option to zip them automatically and store them zipped (to save space).

Ones the artifacts get downloaded in order to be used in another plan/deployment they should be unzipped automatically also.

Feature already implemented for Amazon S3 artifact handler:

you can define a maximum number of files per artifact; if this threshold is exceeded the artifact is automatically zipped into a single file, which reduces the number of requests to S3 when uploading and downloading the artifacts and improves the efficiency of the whole process.

https://confluence.atlassian.com/bamboo/artifact-handlers-938641848.html