A: Because your website is a confusing mess and your users are lost in the wilderness. Redirects are for when you can't even bother to use a simple link.
A: Who cares? Just make it short, make it sweet, and make it not-too-long. Humans have short attention spans, don't you know.
A: Ugh, no. That's for real programmers. We're talking about you, the technically challenged. Stick with good ol' fashioned HTML.
A: Only if you're doing it wrong. Do it right, and it's like a wink to Google. Do it wrong, and it's like a slap in the face.