It depends on the website's setting. I have the same phone and there was one website where it took more than 20 seconds.
The power consumption is significant, because it needs to be. That is the entire point of this design. If it doesn't take significant a significant number of CPU cycles, scrapers will just power through them. This may not be significant for an individual user, but it does add up when this reaches widespread adoption and everyone's devices have to solve those challenges.