If that is the case, it probably is not going to be an issue. However, until the game ships there is no way I am going to make that decision based on internet rumor. In addition to registration, if the first patch requires logging into Steam to download and install, then I will likely spend my money elsewhere. So, for this version of Civ, it looks like I will be waiting until after the first patch to decide on a purchase.
On paper, automatic patch downloads are nice, but I prefer to pick when to install patches and may opt to not install for quite some time. What I am hearing about Steam and pushed patches does not sound like something I am interested in.
So far, all the games I have that provide for automatic updates via the internet also provide a "manual" patch that I can download and put on a flash drive.