Strapping is not plywood. Strapping is most commonly shimmed to correct for defects in the flatness of the ceiling joists. Strapping is also a) a regional thing, and b) far less common with engineered floor joists due to their uniformity and straightness. If the strapping is not shimmed, then the strapping will just follow the framing, like the CDX would, and you'll have exactly the same situation with an out-of-plane framing job.
Your background is in drywall, right? I'm a little different - I do it all. From the initial contact with the customer to turning over the keys. I'm hands on at every point of the project. The only trades I sub out on most jobs are HVAC and electrical.
I get frustrated with some of the lag in adopting superior construction practices. 32mm Euro-style cabinets are still resisted in the US by many people, and I'm not sure if it's industry not wanting to retool, or people liking what they grew up with, but 32mm cabinets are superior to face-frame cabinets for most reasons.
Hanging rails are standard for cabinets in Europe and they're an evolution of French cleats, which I'm guessing originated in France (and I'm sure elsewhere as it's an obvious solution). They solve many problems and have no real drawbacks.
Yep, I know. Tiling is one of those things that gets slapped up by a lot of people, including people who call themselves professional installers.
I can install the, what?, three or four pieces of blocking that would be required in an average kitchen, faster than someone could cover a wall with plywood, the cost would be a lot cheaper, I can use scrap wood, I won't be changing the wall depth - which affects window and door trim, eats into floor area for no reason, complicates future work, etc. I've also found that saying, "Okay! That's it! NO more changes." doesn't always work. If something needs to move, it needs to move.
I don't see the harm.
I'm just telling you what I've seen over the last 20 years around here (New England) by many contractors and I can't really speak for them nor defend the practice as they would....Seems to work pretty good for them though....Strapping even not shimmed will help ALOT in the flatness of the ceiling...Atleast to the eye..THAT I do know....Around here even engineered joists get strapped unless in a garage , ect....Interesting your Euro-cabinets haven't caught on here in the States....Are they THAT much more , money wise ??? Or just ugly ??? Got a link with pics ?? I agree on telling homeowners NO MORE CHANGES doesn't always work , atleast untill you tell them they are out of money and going over budget.....Then you get that scared look from them and things get finished up.....