I would also say consider the branding of your piece. If you are only getting a few seconds to get your pitch across (and that's the norm), do you want to stray from your message with another business's branding? It's not the same as a magazine, website or coupon book/ValPak mailer, where your customers are expecting other information or to sift through numerous coupons to find the info they are looking for.
Beyond the other dynamics already being discussed above, I understand that the idea is to get someone else to foot the bill for your ads, but recognize how quickly too much competing info degrades the sales message.
I'd favor staying on message and on target for those types of pieces.