[OttoCoddo]

You got a point. Although with that that option comes a great cost: We will lose portability, speed and even reliability.

Portability: Receiver (or future you) needs to know what you used, and what version even.

Speed: If you want to do the archive part first (tar) and then compress (gz), you will get much lower speed (as shown in the note).

Reliability: Most people use tar with gz anyway, but if you use it with not so popular algorithm and tools, you will risk having a file that may or may not work into the future.

Pack plan is to use the best of time (Zstandard) and if an update is needed in years to come, it will add support for the new algorithm updates. All Pack clients must only write the latest version (and read all previous versions) and that makes sure almost all use the best of their time.