I think we will have to disagree. Years of PROVEN application amongst public aquariums, aquaculture facitlities, universtities, fish farms, etc and my own applications in marine, marine aquaculture, and freshwater are more adequate proof for me that these statements above are inaccurate.
IF what you are saying above is true in application and not just theory, then for at least the last 20 years we have all been doing it wrong. The probability of this is next to none. However as the hobby grows, we uncover new things and new ways of doing it. So there's a possibility, but very slight.
I will concede on this though, and tell you to do as you wish with your own systems. Mine, as I push production to the very limits probably further than I should. And I run population concentrations very high by comparison to most people, I HAVE to have the sterilizers, or run the risks of epidemics I can't recover from. The risk of losing it all far outweighs the minor electrical consumption or the bulbs as they have to be changed.
For me, it's not a hadfull of fish, or even a couple five gallon buckets worth...
I can't risk the shear volume of fish, and potentialy having to break a whole system down on a hunch that goes contrary to world wide application. I have yet to see any data that supports your statements that UV sterilizer will kill off all the bacteria.
But I do acknowledge that everyone's systems are different, and while requirements may be similar. Applications are different.
The absolute best thing I can say is: Do as you wish with your own systems. Do what works for you. For me, I guess I will be a little less effecient on the electrical, but my fish, my inverts, etc will all be healthier.
Best of luck which ever way you go.