I use both. I favor docked at home, but have done handheld to free the tv for someone else (This is rare however).
As for on the go, I have used it between work and nightclass with 2.5 hour sessions. I took it with me on a beach vacation to play in the mornings (in the house of course), I played it while having my truck serviced at in their waiting room, and I take it with me when visiting familly for the mornings or late nights. All of these are undocked scenarios.
While there is no right or wrong way to play, I feel like I am using it for the way it was truly designed to be used. It also paints a picture for why I prefer Switch for multiplats, even at the cost of some visual fidelity.