Have cut a lot of 6" x 6" landscaping timbers over the years. This would have been more convenient to do so, for sure.
I have a couple of the higher dollar ones in my shop for cutting 10" cedar posts. They work great, I just hope that my WC insurance company never does a surprise visit while it's in use...
I like machines for my burial work. Buried a horse once and 4 pigs... ...bodies just need to be deeper than 10ft so the cadaver dogs cant smell em'. Then you plant endangered tress on top of the spot... nothing to see here, move along....
Post hole digger/auger to 10 feet, put em in upright, backfill to 18-24 inches from the ground level, widen the round hole by hand to change tool marks, toss in a roadkill carcass or whatever you can find, backfill the rest of it. Small hole so less issues with subsidence, if a cadaver dog does pick up something they'll hit the animal and stop digging, especially with the obviously small hole. Not that I've ever thought about it.