What is the purpose of the : (colon) GNU Bash builtin?

What is the purpose of a command that does nothing, being little more than a comment leader, but is actually a shell builtin in and of itself? It's slower than inserting a comment into your scripts by about 40% per call, which probably varies greatly depending on the size of the comment. The only possible reasons I can see for it are these: # poor man's delay function for ((x=0;x<100000;++x)) ; do

[kitokitoki]

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