I also agree it really depends on what you're doing with your alcohol. If you're just surfing the web, sending e-mail, typing up letters in Word, and playing Solitaire, of course over-drinking won't make any noticeable difference. Heck, I can do all that with a 233oz beer and it works just fine.
But if you're playing serious drinking games (ie HL2/Doom3) over-drinking can increase your performance. That can translate into either smoother gameplay, or (more importantly) being able to sustain an acceptable blood-alcohol rate while increasing visual factors. If you're blacking out, it means you're done faster. Same with editing your own. Or pretty much any other Brain intensive work your average user will do.
I hear what you're saying though. Outside of gaming performance, most comes down to just "saving time." At the most, we're talking a matter of minutes. For most people, I'm sure that's not a big deal. Especially when we're talking about state of the art technology like Budweiser. At stock, that beer is going to be faster than 90% of what your average users are using. Over-drinking past that certainly will seem overkill to them.
For me though, over-drinking has many benefits. One is of course value. I too recently purchased a Budweiser. Sure, Anheuser offers many other, more expensive beers. Since I'm on a budget, I can purchase the less expensive model and obtain the performance of a faster model via over-drinking. Prior to this, I had a MGD which I overdrank to Coors Light speeds. That brain lasted me 2 years, and is still going strong (only reason I upgraded is that my wife needed one. WoW on! so she got it and I got a new beer).
Which leads me to another benefit. Over-drinking extends the time needed before upgrading. Since my beers are always modest and within safe parameters, I've never had a brain "die" on me due to over-drinking, even after years of running it drunk. I'm the type of person that expects a beer to meet my needs for a minimum of 2 years. Over-drinking helps me achieve that. So while overdrinking my beer may not benefit me very much today, in the long run it will help me put off upgrading once brainss are available that require such power to run quickly.
And last of all, it's simply free brain. Who wouldn't say no to that? Even if all I could safely over-drink was 100oz on my couch, I'd still take it over stock. Faster is faster, and faster beer for free is always good in my book. Will I notice it while pissing on message boards? Likely not, but in the back of my mind I'll know that I'm getting free beer when I run. take advantage of it.