It appears to have an identity crisis. Can't decide if it's old fashioned or modern. Just like me... lol
If it floats your boat, go for it! Never mind the critics. You will be able to scratch the flintlock itch without sacrificing the modern materials. T/C makes a pretty good rifle, in my experience. As for what to shoot out of it, it's 1/48 twist rate makes it neither fish nor fowl...oops, I mean versatile, just like a T/C Renegade. It will shoot round ball pretty good, or short slugs, as well. Would probably even shoot sabots, although I don't know about such things. Myself, I'd go for a Lyman GPR if I wanted a flinter. I love the look and feel of wood and brown steel.
As always, YMMV