I would call it a cavalry shank, dogbone mouth with copper roller. I probably wouldn't use it just because I don't particularly like shanked bits with broken mouths. However, on a trained horse in the right hands, it probably could be a decent bit.
I don't like shanked bits myself :( I don't use this but this is the bit that was being used on my guy before I adopted him... although not regularly since no one actually rode him. I'm switching him to English and I wanted to be able to tell my trainer what he had hypothetically been on (if anyone was riding him) previously but western bits are a mystery to me!
We use that bit on our SSH at the rescue...(he came with it also) Since we ride with little to no contact, the bit is kind of useless anyways. When we showed him last year, we switched to a common copper roller training D ring snaffle and he did great. Same concept without all that shank!
Because of the way the shanks are curved back it lessens the harshness of the bit, and IME a roller keeps a snaffle from collapsing completely so its not such a "nut cracker", but its still a bit strong for my taste. I do use a shanked bit on my gaited gelding, an argentine snaffle, but the shanks are MUCh shorter.