Ghost-writer, define what you mean by "they do the same thing."
I'll give you some differences between using $istok($me,$1-,32) $istok($1-,$me,32) and if ($me isin $1-) and $+(,$me,)
Then compare them to the use of $regex($1-,/(\s\Q $+ $me $+ \E\b)/iS)
I'm not saying regex is a muti-purpose engine to use everywhere in MSL. There will always be downfall, and nothing is 100% foolproof if you intend to be meticulously picky to find it. That really depends on what you try to achieve to get the best efficiency feasible.