As a scientist, the above about the hands themselves (palms) not working isn’t technically true.
At the right angle the tissue of the hand can actually support the weight.
You’d think we don’t have a valid reference for the hands, and yes although there were some forensic studies done to investigate this with ‘suggestions’ that it was possible. The reality is much more bleak. We now have live examples
A few of us were sadly there with the Red Cross recently taking down people that the Islamic State (ISIS) have subjected to crucifixion in Iraq, along side many small villages and towns. In many cases the connective tissue did hold the weight. Of children and of grown men. And they had been there over a week.
If I had to guess, looking at records from Alexander (the great) and others that fathered the technique, the wrist was common. Running between ulna and radius.
Plenty to suggest the same online, with a good case being made for the ease of use. In alexanders day the practice was common and efficiency was key.
Far easier to nail someone at the wrists, than potentially drop them or have to fumble around with rope and straps to aid in load bearing (as was done in some cases).
Either is valid. Perhaps another case of ‘faith guides you which you believe’.