I wouldn't want to get trashed, since phone calls happen. But a beer with lunch, while a common enough thing for me, is something I would hesitate to be seen doing at an office job (unless I were the boss, because it's good to be the king.)
Puritans are everywhere.
And if I had a bunch of solitary work to do? Yeah, I'm drunk in sweatpants. But I wouldn't count on that during normal operating hours when the office might need me in realtime.