The pub should A/B test having the person there, and not there, and look at the bar sales. That would determine if it is bullshit or not.

If the person creates a vibe that gets more people there, e.g. patrons texting friends to stop in, or increased bar sales by people staying longer then it might be worth it.

Of course if the bar hired bartenders that created an atmosphere of fun whilst doing their jobs then that would be even more profitable.