That may be a great option for you. For me, I'm an ultralight traveler. For a month-long vacation I took in Europe last summer, I packed everything into a single 19-liter backpack. I'm already bringing my phone, and when I'm debating whether I really need 5 pairs of underwear or if I can get by with just 4, a separate camera and lens is completely out of the question.
I chose a Pixel 2 because of its integrated camera (and really amazing image processing software) and because of the cost and convenience of Project Fi when abroad. The pictures were all fantastic, and every time I review my photo album I have absolutely no regrets with my decision. There were days when I was in London when I left my wallet in the hotel room, because I could use Google Pay (NFC) for all the public transportation and for (almost) all restaurants and vendors. So, I had navigation, communication, camera, ability to pay for food, and audio tour guides all in one device. And I didn't have to stress about whether I'd lose my bank cards and ID from a pickpocket. If the phone gets stolen, it's locked and encrypted.
I hear you on the price though. A used Pixel 2 in excellent condition is selling for about $400 right now. After looking at my co-worker's Pixel 3 and comparing the cameras, I wouldn't pay the premium for a brand new Pixel 3.