True, but it does have impacts, like you can see less of the overall program on the screen at a time, so to scan through requires more of a look->scroll->look->scroll.
I don't think dense code has drawbacks; people measure in lines of code because they implicitly assume all lines are equal, but that's completely wrong. Reading the same logic when it's 20 lines is much, much easier than reading the same logic when it's 100 lines, because whether you can fit it on a single screen or not makes a huge difference to whether you can comprehend it.
I've worked in/with Perl. Perl is unpleasant because it's inconsistent, not because it's dense - if you want the extreme examples, compare Perl with something like APL.