Just looked at the specs.. 2.7gpm pump. Yeah sounds slow to me!!
Something like that is a great thing to have, i wouldn't turn my nose up at ANY similar digging machine if its the only practical option for someone who wants to own a digger, they're ALL better than shoveling!
As far as turning it into an actual tractor attachment, i think it's a perfectly reasonable idea and it's actually the tractor side of things making it iffy. I say that because the swing cylinder placement on the HF machine dictates a pretty long 'stand off' distance from the back of the tractor, which would make the small BX pretty unwieldy to operate as anything other than a propulsion system for the backhoe because of the added length and weight distribution. It might suck to use for loader or other general work without dropping the hoe off of it. It's (bx) also not tall enough to tuck any of that digger underneath it even if you did for example, relocate the swing cylinder to the bottom. On a larger tractor you could simply lop the tank and engine off the top of the spar and sling the whole spar underneath the middle of the tractor as part of your 'subframe'. I'd say it's a reasonable thing to consider and there's nothing stopping one from making the 'other half' of the machine essentially a standalone hydraulic power pack that could be recoupled to the digging half if you wanted to use them together again. Since it's not using its main 'spar'/beam (looks like a 4x6?) as a hydraulic tank, you could just cut it in half at the yellow line below, and if you wanted to be able to put it back together again you'd just weld some plates or angle irons to the non-digging half, and drill some pin holes in the digging half, and could slide and pin it back together. A couple hydraulic quick disconnects and it's done. Sure, you'd have to be a confident welder but the actual cuts on metal needed to make it happen are extremely simple in this case.
View attachment 98561