closing the eyes when singing is one way to reduce distractions....like the fellow at your table snagging YOUR Guiness...or the short dress of the waitress....or that 'helpful' person down front mouthing slightly different words at you!

as to beards...well...when most traditional songs were composed, beards were quite common. *grin*....maybe it helps with the mood. (I affect mutton-chops of a sort, if that tells you anything)