For engineering reasons, I use single-quotes when I mean to use a literal, and double-quotes when I mean to interpolate. It's just a matter of doing what you're saying, and saying what you're doing.

If I want to use a string constant, I use single quotes. No ambiguity. No mental gymnastics trying to figure out what '@$_$@#!!' means. It's a curse. Ok, so that doesn't come up too often. However, other interpolations, such as 'someone@somewhere.com', are quite frequent.

If I want to interpolate strings, I use double quotes. No ambiguity. It's just a simple acknowledgement that I know what I'm doing, and what I'm doing is interpolation.

People who mindlessly use only a single tool probably don't know there are other tools out there, and, moreover, probably don't really know their own tool properly. If you insisted on using double-quotes everywhere in your code while you worked for me, and in the style you present above, I'd have your attitude for supper. It's simply not conducive to either the workplace or perlmonks.