A culet is neither good or bad.
It is just part of the look of these cuts.
If you don't like culets perhaps consider another cut or one with a smaller culet.
You commented that a culet looks like a hole.
It is understandable you said that since they do sort of function as a hole, optically at least.
When two diamond facets (such as the table and the culet) are parallel, or under a critical angle the light just passes straight through instead of reflecting on the facet.
It is also called windowing.
I have a little green diamond with a culet that was not cut parallel to the table, probably for weight retention as it followed the shape of the rough, yet the culet still windows.
You can see how the culet is at an angle in the bottom of the right pic.
Also on the bottom of the left pic notice the Kozibe effect.
That's where the culet is reflected many times.
This is a look that I love; it's reminiscent of of a bouquet of flowers.
I'd say the culet IS visible in that it is another of the many facets and it part of the look that I like, even in this tiny diamond.
It is not visible in the sense that it would look like a big dark hole in the middle of the diamond though.
Keep in mind that all still pics can be deceiving when it comes to things like "dark arrows" or culets.
A live moving diamond is quite different as these shapes just blend into the other scintillating facets.
Again if you don't like that look there are lots of other cuts without culets.
