I have used this type of joint before. My father once made a indoor swimming pool using 8 by 8 beams. On some of the plates, we used this scraf joint. It was a pain to make, and probably was a bit sloppy, but we did use it.
I am a machinist, but at work where we build high-end yachts, the carpenters use this type of joint all the time. recently I saw them use a crap load of scraf joints in the making of the gunwale. It was made of teak, about 3 inches thick (but rounded in a oval shape, and flared from aft to forward. At the widest part it was perhaps a foot wide. A nice piece of woodwork that is for sure, and the scarf joints had to be perfect as well.
I am not trying to take any thunder away from anyone here, I am just amazed at the detailed joints that can be made between two pieces of wood.
I have no intention of traveling from birth to the grave in a manicured and well preserved body; but rather I will skid in sideways, totally beat up, completely worn out, utterly exhausted and jump off my tractor and loudly yell, "Wow, this is what it took to feed a nation!"