The Geniant blog recently posted a fine article by T. Scott Stromberg, an Information Architect on sketch as a legitimate IA tool.
"One of the greatest advantages of sketching is that it can become a
foundational tool which can easily be used to more fully explore your
design treatments and architectural studies. The ability to hand-craft
wireframes might take some practice, but the benefits gained from their
use in client presentations can be priceless. High-fidelity,
computer-generated deliverables can be a perfectly adequate way to
present your ideas, but there is something liberating about being able
to break out a pen and paper and clearly record creative ideas without
the use of a computer. Likewise, there is also a special credibility
gained with clients when your deliverables are handcrafted and
unique—especially when they excite and empower your audience to
participate in the creative process."