I could fit my entire library on my device if I wanted to, but then it would be only accessible from my device, the purpose to a cloud connect is to be able to access your library from anywhere, and any device and quite frankly to also be able to share my library with a chosen few others (only legal, un-drmed books of course, not advocating piracy here
) I could sell my nexus 7 and get a Sony Xperia Z2 and I'd be able to install an app and peruse my library from the coffee shop.
Aside from zero support or communication from the dev, and some weirdness with the series numbers, Calibre Cloud Pro does this very well. I thought it would be cool if this app would do it because I really love supporting apps that have active and responsive developers. I've already paid for Calibre Companion and I have no regrets, but for a cloud connect interface I'd be willing to make a further donation to support an excellent service. If it can't be done, I still do really enjoy the wireless device feature, that is super neat and I wish my Kindle did it.