I needed a sympathy card in a hurry last week and didn't have anything in my stash that was suitable. Unfortunately, I had used up everything that would have fit. Then I looked at my stack of Simply Sent Kits-and voila! I pulled one of the "Remembering You" cards, stamped the inside and wrote a note, then signed, sealed, addressed and stamped (postage) and it was off. Elapsed time: 5 minutes - 2 to stamp the sentiment, sign, address, etc., and 3 to track down my husband for him to sign. That's a big advantage to having the Kit and making up the cards in advance - you've got a ready supply!
Plus, the kits are small enough (and have EVERYTHING you need) to take with you when you're going to have to wait somewhere. And you don't have to think up a design if you don't want to - you can use what's there and copy it exactly or tweak it to fit your own style!