Washington State uses the UPC code which needs an air gap.
It's purpose to to keep the water "clean" in the dishwasher. Is that important to her?
If an inspector looks at it, it will be needed.
In most other states, you can high loop it in the cabinet area.
Sometimes in Washington, a plumber will install the air gap for the inspector and then replace it with an air gap after inspection.
Frankly, it's just a little cap on the counter though.
It reminds me of dating. If a man leaves one or two visible things on a bathroom counter, maybe it's a shaving cream can; that can be a deal breaker.
A woman can have twenty things on the counter and it looks neat and tidy, but if she sees something out of place, something that isn't hers, then something must be done. A man learns to hide things like razors and shaving cream. And then a plumbing inspector makes the bad mistake of putting an air gap in the womans world; her domain you might say.
Dear..........what the heck is this chrome cap doing amid all my pots and pans, spatulas, can openers, brushes and coffee things? This one thing that I don't understand is putting me near my breaking point. Please remove this ugly chrome cap from my sight, or you're going to have a rough week.
Some people get dishwashers with water heating to sterilize the water.
More on messy kitchens here