1. Straps are less than desireable and pretty much useless if they are actual "straps" and not rigid suports. A strap only gives support one way, it'll keep the wall from flexing out but gives no support for being pushed in like the rigid bench did.
If you look closely, I think you'll find I used the word "straps" in quotation marks. This was to convey an idea of single rigid member, not to suggest actual straps. You focused on the word, rather than the actual idea. You also failed to read the rest of the commentary. I suggest perhaps you're too focused on winning an argument or pushing your concepts, rather than actually helping someone with their boat. This is called having an agenda and is not uncommon on forums.
Also a strap is only anchored with one, maybe 2 fasteners usually in 1" decking which isn't going to hold diddly...
It'll do fine and has done so, on quite a large number of aluminum boats. It might not in a fiberglass boat though, where the flooring has horizontal strength, but little holding power for screws, bolts, etc.
the same with rigid single member braces. Straps and single braces are usually installed at too steep of an angle to be effective, this is done to "save room" and to try to avoid the trip hazard.
Engineering data provided me by my mechanical engineering buddy doesn't support your commentary. For evidence of this, see multiple aluminum boats manufactured with only aluminum ribs for side to side structure. These are often riveted to the hull and are much steeper than any rigid single member brace, their their only tie to the other side being the bend area of rib where it is shaped to fit the curvature of the hull. The have worked fine for many years, without fail in many manufacturer's boats. The structure they provide can be easily duplicated by installing a deck fastened to available ribs, then adding "straps" aka single member braces. What one has done in this case is to duplicate the structure of the aluminum ribs, but increased it's overall rigidity by building a assembly tied to the boat's original ribs.
2. Boxes and storage compartments are a good option and can be very effective for reinforcing a boats sidewalls.
Like on this 1988 Starcraft:
The pictures you show support my own point more than yours. Those boxes and storage compartments are very obviously fastened to the deck (flooring) with "one or two" screws/bolts, which, according to you, "isn't going to hold diddly." Apparently they do, as that boat is quite a number of years old and those boxes, held to the flooring just as I suggested, are still working fine. And regardless if you use boxes, storage compartments or side panels, all you are doing is adding additional stiffness to the over all structure.
3. Rigid solid braces ae another good option, like this:
Looks like a stringer on a fiberglass boat. Would work, but takes up room and blocks anything behind it. Aluminum rigid structural members, aka "straps" will do the same thing, have the same or greater strength and won't rot. Next thing you know, you'll be saying one ought to fiberglass the wood. It appears you might next state suggesting we ought to ditch aluminum boats entirely and build wood/fiberglass ones instead.