That's a valid point, though I think it's evitable (if that's a word) because many editors have visible white space, and it's easier for the eye to catch 4 dots

That's a valid point, though I think it's evitable (if that's a word) because many editors have visible white space, and it's easier for the eye to catch 4 dots after a long tab than to notice that an indentation is 7 dots instead of 8, etc. It also attracts more attention when using arrow keys to navigate the offending lines.