I assume there's lots of stuff they need engineers for - I imagine managing loads of Spotify stores simultaneously has some strange requirements around inventory management, ordering stock from suppliers, returns, providing customer support e.t.c.

Well the valuation process is somewhat automated (they basically need to pull in transactional and user data from shopify into some financial model) which does require engineers.

There like Zillow, but instead of buying homes, they're buying small businesses and given the valuation differences for small vs large business (as said above), it seems like this would be hard to screw up.