the minute you vary from the easiest, people try to steer you back.
In my bathroom reno, I have some 135 degree corners. I have some wall-mount items too. Both were in the plans. At all times, all the people (friends, workers, designers, etc) who looked at the plans had various and sundry weird and perverse reactions when they came across these parts that were NON-standard.
And, to give them their due, I can attest that getting drywall to look good and straight over a 135 degree corner is harder to do than over a 90 degree corner. It is "a pain". But that is just talk. It got done, adn done well. It wasn't a serious impediment, in my book, and not in theirs either when it came down to it.
When vanities have legs on the floor, they love it. When you remind them that you have been talking about a vanity that has no legs, since it is surrounded by three walls, and that for the last two years of planning, buying, demo-ing, and building, everyone has said it is easy and do-able, suddenly they all get a bit different. Sullen or evasive or negative or whatever. And this feeds into your subconscious and you end up giving in after a matter of time. Works especially well when they say things your wife can hear, and she begins having concerns, and even small nightmares. After that, anything they say that is incoherent and unquotable will work. They have her on a string. She is the vactor that transmits their desire for ease-of-work into a need for standard installation. This is what happened in my house.
When plumbing fixtures are deck-mount, they love it. When you remind them that your empty space in the wall is where you have always said you wanted your tub filler valves, the reactions start all over again. Because it's wall-mount.
Same thing for countertops. A faucet on a countertop is like a deck-mount tub filler valve. A faucet with its bolts going horizontal into a wall makes them 'worried'. Even though they all agreed it was feasible.
If you are ready to be meticulous you are ready to put up a wall-mount faucet. Any and all talk about plumbing in a wall (?) is ridiculous and spurious. There is a lot of plumbing in a lot of walls, worldwide. Your faucet is no worse and no better and no different.
If I were a contractor, I would develop the same habits. I would love flat surfaces that rely on gravity to do a lot of the work. Floors, countertops, decks. Bolt it down. Screw it down.
Maybe I would ask to be paid an extra, hourly wage, just for the extra attention a wall-mount fixture would require. Maybe you should.