I buy a system based partially on the promise that it provides for future enjoyment -- and much of that these days certainly centers on my ability to play it with/around my two young kids. But also, I tend to calculate the value of my investments in gaming differently these days as well. For me, for instance:
Legend of Zelda: BotW = ~150 hours of enjoyment
Cost = $300 + $60 (plus tax) = $360 + tax
$360 / 150 hours = ~$2.50 / hour
And, of course, this is the absolute worst-case scenario, presuming that I would only play a single game (albeit a massive one) over the course of the entire console's lifespan. That's a fairly inexpensive price of admission by my judgment, so for me, Zelda alone would have made it easily worth the cost of a Switch.
By comparison, most "normal" games might last around 20 hours, but at a typical price of $60, that's already a higher price of admission ($3/hour) -- even assuming that the console is free (or already in my possession). So justifying a purchase of a console using a particularly lengthy game of unconventionally high quality is a pretty easy decision for me, especially if I'm relatively sure I'll continue to extract value out of my ownership of the console going forward.