Curate, connect, and discover
I know Kaz gets a lot of shit for calling Inej and investment in Six of Crows, but if you take into account the culture he grew up in, it's actually really sweet. Hear me out. When you acknowledge just how important commerce is in Kerch, and particularly Ketterdam, it adds a lot more meaning behind the seemingly throwaway line. Commerce is more than just financial in that culture. It's spiritual. This is a place where the main god is Ghezen, the god of industry and commerce. Their main church is literally called the Church of Barter. Saying someone is an investment in a culture like that would have way deeper implications than simply a surface level business transaction. It's someone you'd want to take care of and protect. Someone you'd want to see succeed and keep close enough to reap the benefit from that success. Someone you'd put time and effort into. It wouldn't be surprising if marriage or having children would be considered an investment in that culture because, to them, it wouldn't cheapen the emotional value of these things but highlight just how important those relationships are. It's not surprising that this goes over Inej's head (and most of the other characters' heads) because she's not from that culture. But for someone who is, it would show just how important his relationship to her is to him. Especially considering he says this while he's putting himself in danger (and probaby a lot of pain considering his leg) just to save her and keep her safe.