LOL:-). Thanks for the article: haven't seen it.

Actually, the main purpose of cat for me is not to memorize all keys of grep. E.g:

Mabooka % grep -w awk *awk* | sort | uniq | wc -l
     10
Mabooka % cat *awk* | grep -w awk | sort | uniq | wc -l
      8
Mabooka %
[download]

It's also good for the prev. command reuse. As for the performance implication: it's minimal (smb. has to do disk i/o anyway).