Here is a nice discussion of the topic for you on woodweb.
As to do installers use cleats in commercial installations, you might want to ask for more context for that opinion. I have personally seen cleat systems used in many commercial installations of cabinets. They are often not done for future versatility, but rather ease and speed of installation.
Cleats are nice for pictures, when there is a large collection of them and you want to move them around. Cleats are also nice for cabinets in a garage or outside storage area, when the items aren’t terribly heavy or hazardous.
IMHO if you’re talking about kitchen cabinets they will likely be fitted to the room and most likely cover most of the walls for optimum storage so I would screw them to the wall.
The other part is getting them on the walls straight. If the rail is straight, the cabinets will be too.
The rails are a fast installation too.
Strength. Look at how the rails are installed. If the rails are well attached to the studs you are in great shape. Rails attached to only dry wall is going to be an ugly mess especially if chemicals are involved.
I use cleats at home because I usually am doing whatever it is by myself and I can hoist a typical cabinet up that far on my on and set it into place. When I think/know cabinet is going to have to support a lot of weight, I’ll 1) put two screws into inside bottom corners of cabinet into studs behind; and 2) fit a 2nd support underneath (I am a belt and suspenders type of guy…):
All screws should be hitting studs, IMO; never trust a drywall anchor to hold over time for heavy stuff no matter how much they are “rated” for…they may hold or they may not. EX: putting them into a wall that also has a door that is open and shut frequently will vibrate/loosen them over time. Ask me how I know…
On the cabinets I’ve installed, I used cleats. Granted the cleats are only there to hold the load while the rest of the cabinet is secured. It makes it easy to get secured & you don’t loose any depth as well as almost no one would even know it was done.
My vote is continuous french cleat system attached to studs. Key here is “french cleat” which has a specific shape. No clue why anyone would object to such short of not wanting to give up the space represented by thickness of the cleat.