Unless there's a notable incentive to owning one version over another, I'm happy just getting it on either console. I don't worry too much about collecting an expensive game for the sake of it if I can have the same experience (on physical media) on another console for cheaper.
With most things, that's how I am, but my exception is with series I have a special love for - Legend of Zelda, Fire Emblem (I have Fire Emblem Warriors pre-ordered on Switch and 3DS), and Resident Evil, for example.
So do you own Resident Evil 2 on Gamecube, N64 and PS1?
I think the 3DS and Switch versions of Fire Emblem Warriors will be distinct enough to justify owning both.
I adore Zelda, but I still don't care to own multiple copies of the same game without incentive. I don't have the Gamecube version of Twilight Princess, or the GBA version of the original Zelda.
see the argument of 'playing the game on it's original hardware' as an incentive to rebuy though - I bought the SNES Link to the Past even though I already had it on GBA for example. It's just not one I worry about too often.