Polite dissent here, Beard. At least whence I come from.
As I said earlier, I often find the mere availability of a "crib sheet" enables me to sing a (complex, long, or newly learned) song with neither a glitch nor a need to look at that paper.
The availability of that 'crutch' frees me from that "OMG! I've forgotten the first word of the third verse!" moment.

It's kind of like a trapeze artist having a net. Probably never needed, but it sure could up your confidence -- hence, your performance.

:D

Genie