Ah, you mean you removed the ( ) braces around if-conditions. Ok.
As far as speed goes, I used to be of your mind set -- back when I owned a Pentium 90 running Windows 95 with mIRC (didn't upgrade until 1999). But even if we went back in time on my old machine, the speed differences between the expanded version of my script and a condensed version would have been insignificant. Honestly, you would have to be in a channel receiving over 100 messages PER SECOND for there to be a noticeable speed difference.
When you begin to code for other people, and when you learn to reuse your old code for new purposes, you quickly discover that the benefits of highly commented and easy-to-read code means the difference between saving time and earning a paycheck... or pulling your hair out while your co-workers point fingers at you.
Programming today:
Besides. The mIRC parser condenses much of the code when the script is loaded into memory.
PS. Legibility is the only way to assure against malicious code. I strongly discourage anyone from running unreadable code -- Hawkee won't even permit unreadable code on this site!