Marketing and demographics.
In today's world, anyone 30 and under, to operate a gadget of some sorts, that gadget needs a screen on it.
If it doesn't have a screen, they are totally confused.
It's funny and may sound stupid, but the more complicated the gadget is these days, for that demographic, the gadget is simpler ! That demographic is used to figuring out these intuitive gadgets and all it's features. Cell phones the perfect example. I am still waiting on the cell phone app where a company will just sell the app and the coils that interface with it. Up to the buyer to buy a shaft assembly and wireless headphones on their own. Its coming...I know it. It will be the easiest way to sell a detector to the new demographic market.
Marketers love to advertise and push for the complexity, advanced technology and thousands of features. Can't blame them though. They need to be ahead of the times in order to sell the product. Check out the car commercials these days. First thing they show is the interior, the big screen TV on the dash and the myriad of options. Whats under the hood is secondary.
Knobs....I don't think they can even spell the word !