[jez]

Something I never understood about this: is the pipe necessary, or just to have another symbol contributing to the mayhem?

    :(){:&;:};:

This is the same number of characters but doesn’t use a pipe, and I was never able to figure out why it seems so universally to use a pipe.

[Ferret7446]

Having a pipe will also eat up your system's file table, so it's potentially more efficient.

[jcims]

One way to find out!