Faust is a ridiculously good card. Playing Anarch means leaning into the fact that a lot of your cards are redundant and/or bad in many matchups, so often Faust lets you sell those cards at a serious profit. In conjunction with Career Faired Earthrise Hotels, you can often reap the full 15 credit swing from your Account Siphons and pin the corp down, while you assemble the suite necessary to get to the Medium lock. (Not to mention the fact that it's much better at breaking Lotus Field than Knight.)
One of the critical lessons I learned from playing Vamp Iain was that, even when you float tags, corps will often let you keep your temporary resources - your Hotels, your Casts, and your Accounts - if trashing them would require their entire turn. On top of that, there's an interesting heuristic that comes with Career Fair whereby a corp will often let you keep a resource you got cheaply, on the theory that they're losing more money than you are in the exchange. So often you can use the Account Siphon credits to slingshot yourself into an even greater lead. Hence the single Vamp - it turns a big lead into a crippling lead.