The value is in when you remember you did something before, but not exactly how. So you just grep or scan through your history, and the files you edited / commands you ran are likely to refresh your memory even if they don't exactly capture the entire workflow.
Also means you don't have to retype complicated commands too often.
Practical example: I remember I cleaned up some calibre converted epubs with perl a couple months ago, because they had a piece of text injected by some kind of generator on every page. It took me some time to figure out the exact replacement patterns, and if I were to do it again, I just need to do:
