Just having the page open kicks my CPU to 4.6 GHz and I can hear my fan going crazy, Chromium 56. Doesn't happen in the documentation or checking the examples.
Well this site is at best sluggish in both Firefox and Chrome on a Xeon with a relatively beefy AMD GPU.
That being said the screenshots don't look so bad. The bootstrap style with lots of rounded corners and gradients doesn't really look like leading edge design, though.
For what it's worth... it ran fairly fast with no hiccups on a Pixel phone. I never really looked into the specs for the phone so... good job Google for matching the performance of web browsing on a MacBook Pro.
2016 and igpu performance is still bad compared to dedicated. With browser rendering supporting GPU accel these days, I'd still never spend money on a computer without dedicated graphics, even for productivity.