Guessing the author means that you can dock it and play on a TV/monitor in your house in addition to being portable for taking around.
The SNES also couldn't play GameBoy games, the Super GameBoy was really just an entire gameboy in a cartridge formfactor.
The Switch has the same feature, you're right. But its designed (and marketed) around it. That's the difference.
With the Switch you can use it docked, handheld, and tabletop (i.e. stand alone).
It seems like a pretty obvious ad though.