mIRC would need a similar construct to denote that spaces need to be ignored during tokenization for a part of or all of a command.
Consistency? Usefulness? Rather than suggesting some silly idea of a function "$sp()", which "skips tokenization" (and thus forces you to do the tokenization in your function call), why not ask for the $identifier functionality of most of the builtins to be exposed? $sp() wouldn't be all that useful- just an aesthetics thing... If you're concerned about aesthetics, there's a few thousand other reasons not to use mIRC.
var %tablename = cosmic greeting
var %itemname = hello, world!
var %space = $str($chr(32),128)
noop $hadd(%tablename,%itemname,hello %space space!)
noop $echo(%itemname $+ ; $hget(%tablename,%itemname))
