There is literally nothing for me to buy right now. Why can't this 10% off be in the form of a code that we can use any time we wish?
Isn't that pretty much what Sony are saying they will give. A code you get to apply to a shopping cart once?
"In addition, sometime this month we will announce that for a limited time, we will be offering a 10 percent discount code good for a one-time discount off a total cart purchase in the PlayStation Store as a thank you to all PSN members."
I suppose the the "for a limited time" could be a problem, depending on how reasonable it is. If it was something like 6 months then it probably isn't too bad. In that time frame there would probably be something you would buy anyway. At that point it probably comes down to whether the code recipient us capable of delaying gratification. If there's plenty of time to use the code and you choose to use it to buy things you wouldn't have otherwise then that'd be your choice (no doubt one Sony would be happy with).
Personally I'll aim to hang on to it until there's something I want. If it turns out there's a game I want, a TV series I want and a movie or two I'd like to see then the 10% could be quite a saving. Then again I've already got more games queued up than I have time to play.