The company I was an early employee of (that ended up being a "unicorn") was not a cool kid, and we certainly were begging people to invest both at the angel stage and (especially) the series A stage. And those people got a really really good return on their money.
This isn't to say there aren't valuable signals perhaps involving "cool kids" status, but there are a lot of diamonds in the rough.
> I figured it would be more fun to be the beggee than the beggor for a change, and I was right about that.
As a much smaller time angel investor myself than the author, I'm still the beggor. You are only the beggee if you are writing 25k+ checks (and more like 50k-100k to really be the beggee). If you are writing 5k or 10k checks, you are going to be begging people to take your money, cool kids or not cool kids. So if you are looking to get into angel investing today without allocating 6-figure amounts to your hobby, I wouldn't advise doing it for ego reasons :)