Many computers don't have support for opening .7z files as opposed to the much more common .zip and .rar files. Nevertheless, you can use 7-Zip to create .zip and .rar files as a way of avoiding this issue.
Allows servers to be administrated via scripting without any GUI running on the server. Makes it more stable due to less possible bugs/patching. And a smaller footprint makes it good for running VMs/containers in the cloud.