I purchased these MGN15C a while back and didn't really know they were miniature blocks/rails.

I see by their spec they are not as strong as the normal size rails, bit don't know how to translate that into real world use.

Are these only good for 3D printers, laser engravers etc or am I underestimating them?

Would they fall apart on Z axis of a 2.2kw water cooled spindle?

Thanks.