I see it all the time on HN, e.g. people bitching about the amount of RAM Electron apps take and the like. Who cares? The average user certainly doesn't.
If anything, 98% of the time when I experience browser performance issues it's network-latency related, or the fact that some page is loading 300 ad-tracking scripts and one of them is accidentally blocking. The only time I really notice client-side execution performance is when someone posts a cool 3D browser example on HN and things slightly slow down a bit on my phone when there are a couple million polygons or whatever. Even then, things are fine on my laptop.