If someone LIKES it on facebook, they now have a direct, reusable channel to communicate with an interested customer. That's worth a lot more than a website visit.
No, I think what you get is an easier channel to communicate with an interested customer, where "easier" is defined as "'interested' customer doesn't even have to visit our site and fill out a form to get an email ... we can just inject messaging into their feed".
Signing up for a coupon, contest, or other deals list via email is already the best direct, reusable channel. FB didn't improve this. They simply created a method whereby companies can take advantage of doing what email marketing does without ever having to ask the user for anything more than a click.
And still, this serves to cement FB's brand and position in the market far more than the interested company's, I think.
