Welcome back to The TechCrunch Exchange, a weekly startups-and-markets newsletter. It’s inspired by what the weekday Exchange column digs into, but free, and made for your weekend reading. Want it in your inbox every Saturday? Sign up here. Thank you for clicking on this email. With a subject line like that you are legend for being here. Of course, we’re talking buy-now-pay-later (BNPL) companies today, a particular part of the larger fintech world that is more than interesting. Thanks to recent mega-buys of players in the BNPL space from Square…