Something looking “safe” varies massively from person to person, based on what they’re used to seeing. The past is safe, because we now know how to react to it and how to prevent certain things from occurring that we did not enjoy.
The unknown is not safe. In a way, neither is the future.
In terms of design, this could mean that someone who only designs gig posters finds that style incredibly safe. Even if they’re then designing something for someone who does not want a gig poster, their instinct is to play it safe, which means you get that style that some people would consider not safe, or extreme.
Safe has nothing to do with minimalism, legibility, or white space. It’s completely tied to past experience, comfort level, and expectations.
Lesson: Fuck safety. Don’t be afraid to make yourself uncomfortable.