To support tar, tar.gz in future.

[Chamlika]

To help users to feed in .tar / .tar.gz directly into OptimizeRasters to work with compressed rasters. Presently users need to use external tools such as (Tartool.exe and others) to unzip data from (USGS/PGC/e.t.c.) before they could proceed with OptimizeRasters to complete their workflows.

[lucianpls]

You could use the GDAL vsitar and vsizip facilities. Depending on the content of the tar/zip, unpacking the data first, using either external tools or python, might still be the better option.