Is this analysis useful? My understanding is that the quality varies greatly from investor to investor regardless of being a VC versus an angel, and their repu

Is this analysis useful? My understanding is that the quality varies greatly from investor to investor regardless of being a VC versus an angel, and their reputation is the greatest indicator of how helpful they'll be. I'm sure an investor from Sequoia is going to be much more helpful than Random Joe Angel. So I feel like this is a field where individual characteristics are key, and this paper turning to statistics, generalizing over many angels and many VCs, makes little sense. What am I missing?