My 2c. I read many threads like this 5 years ago when moving to our new property and looking at tractors. Lots of people chimed in that tractor backhoes are toys, you don't need one, won't use it enough, etc. Didn't have one for the first 2 years, and, after that, broke down and bought a J2720 with a hoe for a really good price. A few observations:
I'm very happy that I have a "dedicated machine" instead of an add on hoe. It's a PITA to get the hoe on/off, if I had it for my Kioti, I wouldn't use it nearly as much knowing I'd have to remove implement/attach hoe/reattach implement every time. In this respect, the posters were right, I wouldn't have used it enough as an individual piece of equipment to justify the price.
Now, where they were "wrong"? I love my hoe. Love it. Us it for all kinds of things, it's absolutely saved me time in urgent care (not trying to lift stupid things) and saved me $$ in rental (I do sometimes get a mini-ex for a few days, but, much less since I got the hoe). Having it hooked up, ready to go, wife gets 3 plants from the nursery, I'm getting it to plant. We have red clay here, digging a hole for a 3 gallon pot is exhausting, with the hoe, I'll do it all day for her, she'll get tired of setting plants out before I get tired of digging. Also, as an aside, when you have a hoe, you do a much better job planting, instead of digging a 3 gallon hole, I dig a 10-20, mix the dirt nicely, break up the compaction, and give the trees a better start. You can tell, the trees planted with the hoe are doing better than those planted by hand.
Adding a thumb, there are just so many uses for it. Cutting firewood, I'll grab the log, lift it, and start cutting. Ripping out vines/small trees, just grab and pull. Moving railroad ties around for landscaping, grab and lift.
I'm very happy I got it, and, I'm also confident, if I wanted out of it tomorrow, I'd get near what (maybe more) than I paid for it, it's a whole machine, ready to roll (and not just a hoe, those can be hard to sell because they are specific to tractor, you need to sell the tractor and the hoe). Also, I do use it for other things, it's much smaller and lighter than my Kioti, so moving mulch around, moving rock, etc. I think I've put about 50 hours on the machine since I got it, at this pace, it'll last "forever", and if I keep it up, I think I'm near the bottom of the depreciation cycle for it. But even if I wasn't, if I get 10 years out of it, and at the end of that time, it's worth 0 dollars (which is not going to happen), it still would have been really inexpensive per year to own this machine.
All that said, if you see a use for one, you will probably love it. I'd just say, my experience, buy a tractor setup for it (not something you plan to take on/off much), and you'll use it much more than one for your "do everything" tractor.