depends on how high the ceiling lights are and how many other lights are in the room. both can work, I like up on shorter ceilings b.c the light bounces around the room rather then casting down . taller ceiling i like down to get the light where it needs to be.

Up fills with dust and bugs and you have to take the shades off to clean, down you can just dust.

I agree uplights make no sense to me , light should be where you need it and in a bathroom it should also be really good lighting

well let me show you my bathroom. at night you will see. 9ft ceilings and less will let the light bounce around the room. Down light can sometimes add shadows. I used to say always down. It also depends on medicine cabinet mirror, distance between the the two, frame depth.... lots to consider.

Some bar style lights are neither up or down just out.....

Here are some images that might help you with your dilemma. Notice the sconces in both?

Residential spaces with BaBoo's interiors · More Info

Lighting as a Jewelry · More Info

it depends on the space.