In this industry, we hear a lot of snarky talk about traditional media and how practitioners "just don't get it." From my vantage point, the same could be said for engagement practitioners; if anything, their condescension comes with a great deal of irony.
Still, there are good points to be made about the viability of pouring resources into traditional, "interruption" marketing techniques, particularly as consumers tune out and the still-rough economy promotes the online shift. But where to start? The following illustration highlights (and grossly simplifies) the problem:

The best reason for going digital—namely, that you can better measure results—should appeal to even the most stodgy print and tv adherent. Now, I'm not going to tell you to dump all your traditional media and invest everything in a spiffy new Web 5.0 website, 30 social media profiles, and the latest Internet thingamajob. We take our role as consultants/strategists seriously enough to recommend cave drawings if they'll best fit your market.
Besides, traditional media can work alongside engagement media under the right conditions, helping to move your customers through the sales funnel. Instead of just blaring your message out to unknown/barely known persons and waiting for sales figures to nudge upward, you can get involved in the process of soliciting feedback and facilitating consumer decisions. For example:
Those aren't revolutionary ideas, but they all have a leg up on traditional-only campaigns in customer involvement and relationship-building. Moreover, they aren't terribly complex nor held at the mercy of expensive, confusing tools—though, as we've pointed out, the playing field isn't quite as equal as we'd all like.
Ultimately, the real benefit is measurability. When it comes down to it, determining the effectiveness of old-school interruption campaigns is a crapshoot. Tying together your traditional and engagement tools, however, provides real insights that help you improve.
Want more details on insights? Check out Mark's piece, "Metrics are good. Insight is better."