I image it's coming out of Square's R&D budget. Good point on the business model too. With this kind of stuff I think you're banking on the in-house expertise/insight allowing you to be first to market with must-have services. This appears to be what the bad mofos at Lightning Labs are doing with Loop and Pool.
I wish they provided more details on how they intend to provide DeFi. Are they building on sidechains, building their own, or building something on-chain with a forward hope of more op codes?
My personal hope is that they build on LN. Its capabilities in the financial realm have hardly been explored. Lots of people get that lightning is great for payments, but did you know you can also add business logic to it? I.e. "send $X to John in such a way that he only gets it if Y happens" -- or from John's perspective: "someone sent you $X but you have to do Y to get it"
Naively, for something like storage you need some kind of watchtower like thing periodically sending incentives John. But for short duration work you can probably achieve it quite elegantly.
Y definitely happenedas a preimage, you can use Lightning to incentivize John to do Y.