That same site does software also, and you have to install on the same day - that sucks. If it is yours to keep, what about when you have to reinstall your os. Many people have to do that, and now they have lost it or any work to go with it. Not worth the trouble to bother installing to start with. Plenty of options to get the same forever if needed it.
Now if it did let you install anytime, all the softwares and probably games are crippled. More so softwares, no updates, no support and other such things. Fair enough but to cripple the software by not installing on a day you want to or after os install-reinstall is a joke.