bradcathey,
There are lots of ways in which $#array can be useful otherwise it wouldn't exist in the language. My point was more about correctness. For instance, if I am doing the following:

my @ucase = grep { $_ eq uc() } @words;
my $cnt = @ucase;
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I have the count of uppercase words, making all appropriate assumptions about @words. I would need to use $#ucase + 1^* since it doesn't produce a count of elements otherwise. This was not clear from the post that I was replying to. * As RazorbladeBidet points out, modifying $[, is one highly discouraged way of accomplishing the same thing.