Sharp image! Yes, the Black Maria required that the world come to it, and for that reason it become subject to theatrical contrivance and artificiality. (Or, equally, the contrivance and artificiality of the photographic studio.) That’s usually the start of the story that has us concluding that the Lumiere brothers were superior to these guys.
But what’s wrong with contrivance and artificiality? Those waiting customers aren’t the most able actors, but the timing and blocking we see here is actually very nice, and very effective. And, as with the only partial fancies of the extraordinarily time-revealing fantasist Georges Meliés, the theatrical shaving here actually has plenty of 1890’s authenticity to it.