It basically boils down to how futureproof you want your purchase to be. Let me use a comparison.
If you'd asked me to recommend you a system between the Dreamcast and the PS2 back in the day and I'd been prescient about the fates of the Dreamcast and the PS2, I would have recommended the PS2 because its future was bright and the DC's wasn't.
Now, look at the Switch and the PSVR: both are fairly recent releases, and their fates are, to a degree, uncertain. However, the current market performance of both devices, as well as a look at the history of hardware add-ons (which, no matter how successful sales-wise, never garnered much support, e.g. PSVR, EyeToy, MotionPlus, 32X, SEGA CD, N64 RAMpack...) strongly suggest that you should go with the dedicated system, i.e. Switch.
There isn't anything to suggest that the PSVR sales and development support will pick up in the coming years. The Switch's future looks much brighter. How bright exactly is what remains to be seen, but it's safe to say it's brighter nonetheless.
Seriously, get a Switch. You'll get more great games down the road. And the greatest games on the system right now are better than the greatest games on the PSVR anyway, save maybe for RE7 if that's your jam. Unless you don't care one bit about Zelda, Mario Kart, or ARMS (or Bomberman if you're a fan).