Big lathes can do any work a small lathe can do; - it has the advantage of mass, rigidity and in this particular case, accuracy. I did some turning for Janger a few years ago that my small lathe couldn't handle: turning a chamfer on a hardened steel 10" pipe. My 12" wasn't rigid enough and kept breaking tool bits. The chamfer would have take 3 minutes on the LeBlonde. It turned out that Janger's 14" lathe, at twice the weight,handled it quite well.
If your real question was "why move that big lathe into your shop", well that's a tad more complicated...
I helped Bert install that lathe into his basement 40 odd years ago, and I really liked using it from time to time. The controls and the way it worked was a dream compared to my 12" 750 lb lathe. And Bert had no way to get it out of his basement. The moving company quoted 10,000$ to move it from the basement to the back yard. So after a sweetheart deal, I agreed to buy it and move it to my shop. The bonus is that it is essentially new, with only about 100 hours of time on the headstock and ways. and the included tooling was about 3 - 4 times what I paid for it. But the price isn't the whole picture as I have a couple hundred hours of 'sweat equity' into it by now.