$170 base price is a bit odd. Chromecast Ultra is $60, which means they are selling the controller for $110? For comparison, you can get an Xbox or PS controller for ~$60.
Never mind, I was on the Canadian site for some reason. $130 is more reasonable, but I would still have expected them to sell the hardware at a discount to get more monthly subscribers.
Also, you don't get to own Destiny 2, just play it while you have the pro subscription (i.e. similar to Xbox Live Gold benefits).
You are getting the hardware at a discount, and besides this is just the founders edition, you won't need a chromecast ultra to use Stadia in 2020. You'll just need Chrome.