It's American,(see footnote) It's Cheesy.
That's probably why nobody turned up when I put on a show featuring our own quartet and some other stuff.
I did barbershop for about a year, learned heaps.
Just the same as an Accapella concert, it is a passive thing for the audience, making up improvised harmonies is frowned on.
I much prefer the audience in a folk club that will join in and create glorious never to be repeated spontaneous harmony.
There is definitely such a thing as too much rehearsal.

In Australia It's sooo cool to be antiamerican, even though we wear baseball caps on backwards and call each other dude

That's my two bob's worth
Want fries with that?
Keef