Why the last four words? Anytime, I'd have said.

A very few kegs can, when equipment is meticulously maintained, be fair enough. The problem is that very few of those selling keg know good from bad, and even fewer will put in the effort. Most of those who will put in the work do so on real beer, unsurprising when you consider how much better their efforts may be rewarded.

My ceilidh days are past now, but as I recall it too much of any drink tended to impair, but a modest consumption of decent (proper) beer aided enjoyment without taking too much from the performance.