It does matter for RF, as TFA says. So the tools do it for you. Since it's automatic and easily done with the tools, everyone just does it. Sure, you don't hav

It does matter for RF, as TFA says. So the tools do it for you. Since it's automatic and easily done with the tools, everyone just does it. Sure, you don't have to shy away from 90° but you also don't have to avoid it. I strongly disagree with "looks wrong". It's simply an aesthetic choice, there is no right or wrong about it. I wonder if they did this kind of optimization back in the day when traces were hand-taped. The sensitivity is to rise time, not actually frequency, so even for the slower designs of the day, maybe 45° or arced corners were still useful?