The same reason why people pay hundreds of dollars for a certain allotrope of carbon. Marketing.
If you want to know wither something is effective, the place to look is the commercial sector. Glow Beads and other lumo material is not widely used on commercial Long line, if it provided a significant benefit it would be used. If you want to use light, go the whole hog and use a glow stick. If Lumo was effective it would be find on almost all Jigs, lures and spinners. These devices relay primary on sight to attract fish, have a look at Rapalas’s selection, they are the biggest lure maker in the world in a extremely competitive industry, how many of their colours include lumo? , look at any of their competitors, how many of them include lumo?
I sometime use lumo tube and beads not because its going to catch more fish, but because they are widely available and often cheaper then their non-lumo alternatives.