The dining plan at DLR isn't "worth it" for a lot of people. Certainly isn't for our family!
You get dollar-for-dollar vouchers. The problem happens when you get a snack (let's say a churro) that's $4, but your snack voucher is for $5. You don't get the $1 in change, or even a $1 voucher to use later... you just lose that $1. Of course, vouchers for larger meals could be even bigger losses!
So, you pay for the vouchers, then end up still either spending money (to cover the difference on a tab) or losing money (when your voucher is worth more than your tab).