He's a semi carry strength hero because his farm is amazing. He can grab jungle on the way to lane, which he gets bonus gold for, and he can get a free 3 HP regen or 3 armor if you find the right creeps. Switch to net mid game and crit, frost armor, or minotaur stun and you have a solid mid to late. Some even get a hand of Midas on him so they can get even more farm.

You don't need to take him mid, you don't need to help others, and you don't need ganks. You just need to farm, that is, if you're trying to carry. And because he's strength, his tankiness builds up too. If you can't farm up a radiance, get some strength item. A reaver's good, and builds into a heart, but it's not much less gold. I think early bracers do make your life easier though. A RoB will also give you armor for anti harass and builds into a vlads if no one else will get it, but won't help your damage and therefore your farm.

I dunno, try midas, bracers, or other small farming tools if you're having trouble getting the radiance.