Necrolyte - Why is it not picked often in CM/Pros?

So for the last few weeks me and my mates/team have thought about the Necrolyte and using him as a carry in a CM game. Today we finally found a decent draft to go "yeah, this should work" and the result

https://dotabuff.com/matches/100255818

I only used my ult about 4 times, in terms of drafting, it was perfect. the OD and his aura keeping my mana up, and my sadist keeping my mana up while healing.

But it did make me thing, with that much power, why isn't it picked up often in CM/Pros? Ive seen it a few times but not a lot. The Sadist/Pulse makes him quite a strong force as he can constantly heal and do dmg, then his ult is great for finishing people off. Is the main reason the fact he is often thought about as a support? I'm very curious about it