The back sensor had an indent too, so you could easily feel it. Hold your phone in your hand. Where does your index finger sit? If it is on the back of the phone, that's where the sensor was. It was very natural.
Sure, but I'm talking about where my fingers first reach when taking the
device out of my pocket.
In that case, I'm grabbing it with my thumb, index finger and middle
finger, and since the phone is seated upside down, my thumb reaches the
home button before I'm even holding it in my palm.
On phones with a fingerprint sensor on the back, I first have to get a
full grip, and then I can reach for the sensor.
I much prefer having it on a physical home button. You can still feel a dent, but it takes even less effort to reach for it with your thumb.
(Well, I think the Pixel never had a home button, and by now it's unfortunately disappeared from other phones too...)