This might work for the first generation of steam users for now, but eventually they might require some kind of verification for old Steam accounts. Also remember that Steam is providing two things - a license for the games and a service to download them. I wouldn't expect a court to agree that a relatively low one-time fee obliges Steam to provide your or your heirs a service in perpetuity.

Why take the chance for games that you can get DRM-free and transfer independently from some live service.