Should HN Get 2FA?

Never. 2FA is a suicide pact for any online service if it doesn't have high touch customer service like a bank. A certain fraction of users will be locked out without recourse each month and the user base will decay like a radioisotope. Every time a service requires 2FA I rethink if I want to stay with it.

Dont exactly see the appeal of what someone with my login credentials would do on HN.

To manage it, probably. For the rest of us, probably just simple / basic password complexity and some attempt at detecting brute force if that is not already a thing. My personal preference for any site would be to also have an option for cidr/IP approve-list.