My husband uses it more than I do, but I mean there is the online play aspect that's worth it if you've got games/the desire to play online like that. For him/us I think it's the NES games that you have access to, which they update fairly often. Sometimes it's nice to just play some old school Mario game like you're a kid, you know? We also have the SNES Classic and play that as well, and I don't think there is a lot of overlap between the two.
I am garbage at old school Nintendo and still enjoy it.