The Taskrabbit problem is: find people this way, but valuable relationships you take offline (though perhaps still manage through email and pay through paypal)
The Angel List version of this is: I am investing a lot of money in your company. You reach out to me and we just do our deal offline (well, through Hello Sign and bank wire).
I mean, there are not THAT many investors in your company.
So: Angel List needs a way to make it worth it for ME to invest through it, not just discover through it. Or they need to make their money as media not transactions (which may indeed be how they are doing stuff).