In a full floater the axle is splined at both ends, and does not support the wheel. The axles only transmit torque to the wheel.
In the illustration the axle has a flange at one end to support wheel. It also shows 5 lugs. If depicted accurately it's probably from a single-rear-wheel Transit instead of a dual-rear-wheel heavier-duty model. That's not to say the DRW axle may not be a full floater, but I wouldn't go by this illustration.
Personally I think that as long as the axle is designed for the intended load it doesn't matter that much whether it's full float or not. Most all large truck axles happen to be full float but it doesn't preclude a non floater to be designed to carry more weight. I'd guess the reason we don't see that more often in mid-size trucks is because it would cost and or weigh more.
Im having a hard time reconciling that drawing as that compared to the illustrations I see online showing the bearings and bolt setups.
Is being "rated" - good enough?
Depends on the owner I guess, I can only go by my experience with both.
With the axle type the rear end beef seems to follow.
With full-time work at rated load -the semi and non floating types (most 1/2 ton vehicles) didnt break on me, but either directly wore enough to warrant significant work with leaking seals, and rear end clean outs.
After 10 years, some were starting to "buzz" - where the full floating vehicles not only wear less, leak less, but seem to wear out the components around them less.