That is too bad, for sure. I love my LED lights!
However, when I got my Pixel 2 in April, I knew it had the setting for LED/AOD and for three or so months, I didn't use either. I never really missed any notifications - I just double-tapped my screen quickly to see if anything had come in. I had been quite surprised that I didn't need the LED.
When I stumbled upon the actual setting to initiate LED, I turned it on. I've been using it for about 2-3 months and like it. But I feel like I could do without it as well.
I'm not saying it isn't a big deal to not have an LED on the Pixel 3 - but perhaps with using AOD or the double-tap-to-wake function, you won't find yourself missing it as much.