@JJoyner1985 said in UNIX: What Is a Tarball:

So, do you think the reason I am seeing a lot more gzip in use with tarballs is due to the familiarity of gzip and the negligible difference in the compression between it and bzip2? Basically, bzip2 doesn't make enough of an improvement with sufficient regularity to entice people to move away from gzip, or is there some other benefit to gzip that my training material hasn't covered?

That's correct. The difference between the two is generally small enough that people are not concerned. And lots of systems still don't have bzip2 installed by default so if you want scripts or whatever to work universally you often use gzip because you know that it is always there and predictable.