[oak perl] stay away from nested array(s)?

[Sandy Santra]

The Llama book includes an admonition against adding "new
items to the end of an array by simply storing them into
elements with new, larger indices" (3rd ed., page 46). 

Is the book trying to dissuade me against:

@biglist = 1..300000;
@biggerlist= 1..700000;
@maybetoobigalist = (@biglist, @biggerlist);

I'm asking because I'm not exactlly sure if that's what
they're talking about.  Or/and it's also to encourage a
newbie like me to learn and use push (instead)... 

Am I on the right track here?

--Sandy Santra