A pure mage does not benefit from Smithing. The only thing you'd ever want to smith is jewelry and you can already do that straight fro mthe start. If you want to craft beautiful clothes, you'll have to sue mods. There are no jaw droppingly beautiful clothes in vanilla.
However, a mage profits a lot from enchanting (just like everybody else does). Especially if you're focusing on Destruction.
If you're playing on higher difficulties, it's worth it to invest in some dependable armor for your mages (either through Light/Heavy Armor perks or Smithing). I hate Flesh Spells, because they cost too much magicka and they generally don't yield great result (since a lot of enemies will just go through all your armor in one-hit).
On the aesthetic, you should try out combinations. IMO, Armors usually looks better than clothes.