I think maybe they were saying that scripters should always use the chr references in their scripts, period. Which i personally think often makes mirc script harder to follow, and unless you have the chr references burned into memory, no easier to determine which it is than with the 'boxes'.
Regarding OP's original suggestion, i dont think its a good idea at all, this would cause more problems than solutions. For example the following would cancel the 7 unadvetantly
//var %x = 2some 3text | echo -a ::7 $strip(%x)
