Additionally, why would the VCs prefer cash to shares in AngelList? VCs are in the business of putting money into rising companies, I'd assume they'd much rather have shares in AL than having to return a pittance of cash to their LPs.
I'd also make a large wager that none of the founders of PH have "FU" money as a result of this deal. AL putting their scarce cash into the pockets of founders is a very very stupid way for them to invest their money. You'd much rather structure the deal to give the founders AL stock so they have an incentive to work hard for you instead of just waiting out the deal and pocketing your cash. Remember that AL has all the leverage here, they can structure the deal however they want.