Roleplay wise, I can see how it could work. If your character is a cold hearted mercenary with no ties, it fits perfectly.

But personally, I don't think it's worth it. Having your identity erased, to the point that no one in the world could recognize you even if you told them your name? That basically is the same as being dead.

No perks can compensate something like that.

I've never been able to get that far in the Thieves Guild. But my understanding is that the effect of wearing the cowl is not permanent. Therefore I think death is probably not the best anology. I think a better anology might be amnesia.

It is a mask, only a very powerful one. People cannot recognize us when we wear masks in real life but that does not mean we have died.

Besides, looking at the cowl's page on UESP I read: "Wearing the cowl does not truly give you a second identity. The majority of the game's scripts are not set up to treat you any differently when you are wearing the cowl. Therefore, other than the specific effects noted in this article, most aspects of gameplay are not altered by the cowl."