Shanked bits are the 'traditional' gaited horse bit. This seems especially true for Tennessee Walkers and Missouri Fox Trotters. I was looking at an old photo of me on my TWH when I first got him. The old owner had him in a bit with shanks that were at least 6-7 inches long! With a tight curb! OH MY GOD.
That old boy was so patient with me. I was so novice I hadn't a clue.
Personally, I ride my horses (including my MFT!) in a hackamore. They do just as well, if not better, than with a shank bit.
I use a fleece padded one with awesome results. My MFT, Loki, was NEVER ridden in a hackamore before now and he responds just the same as he does with a bit. Honestly no difference!