I think that it is an appropriate marketing campaign. "Drinkability" is part of the "overall impression" category when reviewing beers. I think that this Bud Light campaign is attempting to reach out to craft beer drinkers in that regard. It's also the beginnings of a possible beer education that they can use to ease people towards their new American Ale.
In general, it's a good description that many would agree with. I've seen many people say that there's an appropriate time and place for just about every beer. This statement is usually followed with "I'd drink a few Bud Light's or PBRs after mowing the lawn or doing some yardwork." Heck, even BJCP style guidelines states that the overall impression should be "very refreshing and thirst quenching."
Now that I've said that, I won't be having a BL smoothie any time soon, but I can see where they're coming from. I understand the desire to bash BMC, but they are accurate examples of certain styles. I can also see that the ads work. I saw a neighbor the other week bringing a 30 pack into the building. They told me how they hadn't bought any beer in a few weeks, but seeing all those drinkability commercials gave them the itch to go out and pick some up. Seems like as good a reason as any to get DVR