That brings brings me to my next point: Having bagel slices means the ratio of cream cheese to bagel is more equitable, which I have absolutely no qualms with. It's also more surface area to spread cream cheese over, which means a better and more even bite each time.
Finally, these leftover pre-sliced bagels can be repurposed to make great bagel chips. They’re delicious after going through the toaster (we tried it), and the leftovers can easily be brushed with butter and garlic salt and transformed into a simple crouton or a great cracker for a cheese plate.
The only real issue I see is if you have one of those fancier bagels with loaded toppings; those, I would agree, are best consumed in their whole, length-sliced form. Otherwise, plain, everything, egg, sesame -- they all would taste great sliced.
When I asked the Panera employee to slice my bagel vertically, she didn’t hesitate or look at me funny. I asked her if people ever wanted their bagels sliced this way, to which she replied she’s come across it, but “it isn’t very common.” But maybe it should be.