I'll quote one of my buddies from a few weeks ago; he was playing not-great, and someone wondered if he had eaten a good breakfast:
"Yeah, I ate. I guess what I need to do is just drink beer until I don't care, and then I'll play better. Seems to work okay for EarthRocker."
I struggle with this often. Back in early high school, in Driver's Ed, they showed us a fim that documented the effects of alcohol on drivers of different ages and genders. They drove through a course sober, and it was timed; then they sat down for a drink, then drove it again. They did this several times. Their speed/times actually improved after the first drink, and the second. Beyond that, they started knocking over cones, etc. I remember watching one of the women, crying at the end about how she just had "no idea how bad it was" after only three glasses of wine...
As someone else noted earlier, in Bowling, Darts, and Pool/Billiards, I find that a certain amount of aclohol seems to help, whether it's a steadying of any nerves or a temporary improvement of focus. But it goes sideways pretty quickly. Same with DG: there's a perfect equilibrium achieved after a few holes with maybe 2 or three strong beers. The trick is to switch to water, and then maybe crack another brew on the back half if you really want to...I've gone 8- or 9-under on my home course through as many holes, only to start going to sh*t later, when I added an extra snort of whiskey or something...It's all about lubrication and antifreeze... until it isn't.
I've been over-buzzed plenty of times. Luckily, there was no money on the line. Maybe my bag tag, but really, how much can I care about that? If I can't stay sober long enough to play a full round with some success, it's my fault, and no one else's.
So I guess I'm saying that yes, alcohol can be useful. It can also be a crutch. Mostly, it's just something that, like anything, should be used in moderation. There isn't one singular factor that totally kills one's round. There are usually several that commingle and lay waste to the mind in subtle but real ways...
(Don't get me started on the Devil's Lettuce. I love it and hate it, all at once. It's a paradox, I tell you.)