I'm confused. I just worked my way up to 100 smithing and unlocked Dragonscale. Yet, when I went to craft my first suit, I noticed that Daedra was listed at the bottom as if it was the best, despite the fact that it only requires 90 smithing, not 100. I looked at the stats that would result from crafting the chestpiece of each type and Daedra, indeed, does appear to be better. Can somebody explain?

What's there to explain? Daedric has always been better without smithing.

As long as you can reach the armor cap, which is 567, it doesn't matter.

Besides, Daedric materials are far more rare than Dragon Bones/Scales.

In other words, if you've got the mats to craft Daedric, there's no reason to unlock Dragon smithing? It's pointless?

They're practically on-par, main difference is cosmetic and that Dragonscale is light armour (versus Daedric being heavy), imo.
Dragonscale looks far better than that horrid mess that is Daedric.