I feel that the reason why are marketing it as a home console you can take on the go rather than a handheld that you can dock to a TV is because they don't have to worry about the handheld aspect of it. Excluding mobile phones and such, Nintendo has a really tight grip on portable gaming. Sony seems to have abandoned it, and no one else is stepping up. When you really think about it, the Switch is quite a bit more powerful than one would expect from a Nintendo portable. Like, the GBA is a portable SNES, but weaker in numerous aspects. The DS is a portable N64, but relatively weaker. The 3DS is a portable GC/Wii, but still weaker. The Switch? The pattern would assume a portable Wii U but weaker, but that's not how it is. It's fairly stronger, and that's not including docked mode.
In all honesty, the Switch is what folks were kinda expecting the Wii U would allow, the latter which didn't.