I think too much of myself leaks into my writing when I'm tipsy - so while it certainly can help me connect if I really want to emotionally charge a scene, or if I'm writing about myself in some way, it tends to compromise my writing if I'm writing a character dissimilar to myself or some such. I think the style of my writing is clearer when I'm not tipsy, too - I tend to write in a fairly convoluted manner, and it's easy to slip up and make grammatical mistakes or lose track of my own sentence if I'm inebriated.

On the other hand, considering how many great writers have been known to drink as part of their lifestyle (sometimes to excess!), clearly you're onto something. ;P