As starbucks_mafia pointed out, they aren't the same thing. They are very different things. And they follow a specific structure defined in basic logic, so you can't just go and change how it for mIRC or you'll really mess people up. A new operator would work, but as mentioned, $istok works just fine for things like your ON/OFF example if you really didn't want to use the IF's.
Look at it like this:
if ($3) { }
That checks to see if $3 is not $null/$false/0, right?
if ($1 == !game || $3) { }
That checks if either $1 equals !game, or if $3 is not $null/$false/0.
Even combining them:
if ($1 == (!game || $3)) { }
It will still check the same comparison (if $1 equals !game, or if $3 is not $null/$false/0). In logic, that is NOT checking if $1 equals !game, or if $1 equals $3 no matter how you want to place your parentheses.
