To be honest, it's not something I need.
But I think that's why it's appealing; it's kind of a treat. Right now, that NES classic is still in it's box, but I just can't help just holding the pretty packaging, looking at the box art and chortling away with joy. Yeah, I'm worth it.
Buy a brand new game for c.£50, or pay a little bit more for a whole machine, with two controllers to play co-op or competitively, a stack of nostalgia, and the likelihood that it'll be hacked in roughly 25 minutes should you be inclined.
The hacking bit is interesting, because I haven't actually done it to any of the classic consoles (and may well never get around to it due to acute diagnosed idleness), but just the fact it's an option and seeing what other people do with it makes the whole thing more exciting.