I should have clarified what I meant by that. From what I understand, I can't actually download a .pdf from the browser version (the website isn't very clear, If I misunderstood, I apologize). To me, "purchasing" entails that I get a non-DRM'ed, offline copy in some standard format. Is the desktop version separate from the browser-based version, or is that the same thing?There is a desktop edition. Other have commented on it above.
EDIT: Let me say, I'm not trying to force my views on anyone, I just have no interest in web based subscriptions. That's the same reason I'm content with FreeBSD for gaming, I can run my GOG games just as well with WINE on any *nix OS that it's available for, while not being interested in Steam.