I'm of two minds about gift cards. I sort of agree with Hutch's view that they're sort of a lame, I put no thought into this gift. They're definitely inappropriate and total cheese in a lot of situations. Like, if you give your significant other a gift card for your anniversary, that's so insulting.
But for other people I'm not super close to, I'm OK with a gift card. My aunt and uncle I see every 2-3 years, yeah, I get that they probably don't know exactly what my hobbies are and what I might need or whatever. So instead of buying me something that there's a very small percentage chance I can use, a gift card seems like a practical middle-ground.