I humbly disagree. A product is assumed to run "as advertised". Unless the distributor could prove that for instance you have taken part in the discussions here (so that you would have had the chance to learn about the Steam-binding), not pointing out that a third party service was needed seems to make the whole transaction void. At least it would be left to the interpretation of the judge whether signing on to such third party services (with all the discusssed implications) may impose a barrier the customer does not want to cross. It seems to be similar to advertising a car model without mentioning that it runs on natural gas, which in many areas is not as easy to get as normal gas.