I agree on most points he makes, except it doesn't have a free floating exchange rate or some weird algorithm maintaining a peg. You also can't create more supply than there are willing temporary sellers of BTC.
Maybe it's only used as a way to keep future main chain fees in check? As soon as fees on main chain drop, Liquid loses its main benefit and people start transacting on main chain again.
But yeah, having a known federation of people in control doesn't sit well.