Our games are rarely sober, except for whoever has to drive (in normal times, of my four players one lives here, another lives in our building, and two others are a couple who drive together - meaning only one of five of us has to stay somewhat sober). I firmly believe it makes for a better and more enjoyable game - people don't take it as seriously, are more willing to laugh at their own foolishness, and are more willing to put their characters into ridiculous situations.

(edit to add: that doesn't mean we get falling-down drunk)
The flip side is that as DM I might not play the monsters to their full capabilities; this tends to cancel out somewhat any tactical mistakes made by the players.