Yep, I see it as a two-way street. Unawares steam users will get the benefit of improved drivers (stability/performance) that they might not have otherwise realized was available to them AND AMD will get feedback from steam regarding driver instability issues.
Basically we all get to benefit from steam giving AMD access to a huge testbed of reportable results from driver upgrades. AMD will be able to identify driver issues more quickly because their reported statistics will be much higher, steam isn't about to lose money and clients over buggy AMD drivers so steam will be in the customer's corner driving AMD to improve drivers rapidly.
(kinda like a pseudo-WQHL process)