The Steam Hardware Survey is an incredibly valuable resource, what with it being freely-available, constantly updated, and sourced from a population that makes its sampling biases generally easy to identify and understand. It and the Backblaze hard drive data are almost unique in how they provide real, large-scale data about computer hardware.
It has his flaws though and is somewhat archaic. I emailed Gabe about this a while back but got no response.
The user (or bot) doesn't have to provide the hardware information, but does have to provide consent for that information to be sent to Valve. Bots have no strong reason to prefer "yes" or "no", but if you have to implement code to handle that dialog box, answering "yes" might be seen as the more human-like behavior.
It's interesting how you can practically tell how many people have a specific processor nowadays (12 core = 5900,7900,9900x, 14 core = i5 14600k, 245, 20 core = i7 etc)
Pretty cool