The key though is you also have to present them at least 2 - 3 very radically different versions of the same thing.
Each tool has a different purpose at different parts of the design stage. When I'm in blue sky ideation phase, I don't want users to be thinking about colors and proximity (although I do, even at that stage, care deeply about information hierarchy and hate sketch tools that make information heirarchy hard to design for). It's when I'm more in the narrowing down stage that I'll move to more higher fidelity tools.
I've always gotten so much complaints when wireframes look too much as design, they will start making all kinds of comments about how it looks instead of focusing on structure.
I used balsamiq wireframes tool a lot for that reason.
Personally I've found basic shapes and text boxes, or felt markers, infinitely more helpful at getting direct feedback from users.
I like the style for its aesthetics alone
> A set of common UI elements with a hand-drawn, sketchy look. These can be used for wireframes, mockups, or just the fun hand-drawn look.
You made up all the stuff about users and feedback. It isn't on the page and it isn't in the README.
This used to work with actual paper prototypes. But going the extra length to make UI designs look hand-drawn, when the users know full well they are computer generated is just busy work.
Showing the users what the actual design might look like works better and it actually captures important design choices such as shapes, colors, proximity, etc. that users care about.
I have been to many UX tests. Regardless of sketchy design look or not, the user will either have no problem providing feedback or they won't give useful feedback. It mostly depends on the person, not on what you show them.