I think the size of those trees are a bit deceiving in the video. A lot will have to do with your soil type. Right now it is so wet around me things come up pretty easily. You aren't going to pull an 8" base tree out with your tractor, but you will be surprised by what you can do. Good thing about this particular puller is that if needed, I have no hesitation about renting a skid steer to pull bigger trees without tearing the puller up. It's impressively built in person.
And to add, if that is what you are going to be doing, a grapple for that task is basically useless.trying to push a tree over or to even get into the ground enough to try and get at roots is very difficult due to the width. I guess it could be done, but so time consuming you would hate it.