For road bikes, or all bikes? is the 1 1/8" straight headtube being replaced by 1 1/8" x 1.5" tapered headtube? Does this give additional support to the fork? Do you think it's safer when you have a carbon fork with a carbon steerer tube to have this taper?

I'll be ordering a Ti road frame soon and wonder if I should be getting this new taper. I already have a 1 1/8" carbon fork with a carbon steerer and if this is going to be a big improvement, I'll order another fork that's tapered 1 1/8" x 1.5"