A protein with a high intrinsic brightness that does not fold well or can not be detected in a microscopy setup has zero practical brightness and is of no use. (blog.addgene.org)
Astronomers use supernovae in the same way, since supernovae often explode with about the same intrinsic brightness as one other, and then appear dimmer depending on how far away they are. (newscientist.com)
Because of their identical intrinsic brightness, they earned the nickname «standard candles.» (discovermagazine.com)