Except Nintendo is putting their money where their mouth is, and the launch title for this portable machine is also their most ambitious home console game ever.
Basically.
People don't care about God of War: Chains of Olympus on the PSP or Uncharted: Golden Abyss on the Vita. They're second-rate spin-off games in series that have better games on all fronts, including graphics. Sony thought that would be enough and the portable factor would make up for their shortcomings, but that's not how it works apparently.
With something like BotW, you're literally getting the latest mainline Zelda game, which is also the most ambitious and technically accomplished in the entire series. And you literally can't get it anywhere else, except as a (slightly) inferior version on last-gen hardware.
Also, it makes much more sense for Nintendo to market the system as a hybrid home console rather than a hybrid handheld:
1) Conceptually, it sounds more impressive than just "here's your handheld; btw you can hook it up to your TV"
2) Tying into JoshuaJSlone's point: the system is technically advanced enough for most people to think it provides console-quality performance in 2017. And there is no better showcase of that than Zelda (and Skyrim). Large open-world games with decent graphics and framerates used to be unthinkable not so long ago. BotW tells consumers "that's it, you get state-of-the-art console gaming, but you can finally also bring it on-the-go. It's magic!" It doesn't matter than people on GAF can tell the system is inferior to the PS4. To the average consumers, it's almost identical.
This brings its value up considerably. I wouldn't be surprised if, to many people, the Switch already represented the future (much like the Wii did back in the day) compared to "mere regular home consoles" like the PS4 or even the PS4 Pro. "What, you can't even bring the system on-the-go? What is this, 2016? LOL"
[EDIT] Also, yeah, ZORG isn't that impressive outside of resolution. Granted, it's 2 years old, and mobile gaming sure has come a long way, but it's still pretty ugly technically when compared to even the PS3 Wipeout games. We should get comparison shots of FAST Racing League running on Dolphin at 4K. It really does look like that game. The cars especially.