That's kind of Google's modus operandi though, isn't it? They don't make desktop apps unless there is a distinct need for it (Google Earth, for example). They are all about the web!
Furthermore, Google Earth only existed on the desktop because Google bought Keyhole who made the app. Google would not have made it if it couldn't be on the web.
by the way, I can find a million alternative cloud based photo services, all with comparable features. On the other hand, there are very few desktop picture managers, especially on windows and linux.
Because a free great desktop app, paid for by a freemium (or free-for-ecosystem-lock-in) online service was quite a thing, but never a permanent/sustainable one. I suspect that I will use an utterly outdated version of picasa for quite a while, because it already wildly exceeds my demands for an offline snaps-management application in its current version. Hope they did not sneak in a kill-switch in a previous update.