IMO as one with no real scientific background on the subject.....
UVA or UVB just isn't a necessary part of any lighting system for Aquarium, vivarium, terrarium, etc, etc. And not even is it of value for growing plants. So the only plus for advertising a UVA or UVB value in lighting would be to show that your lighting system is lower in UVA/B than other competitors.
Fad's come and go.... uv is one of them.