Why do people always have this monolitic view? Sure, I'd rather keep the files on my *personal* PC on my local disk and edit them with desktop-based applications.

But for large corporations, especially those with mobile users, this sort of web applications (when kept on internal servers) could be a great way to avoid the maintenance hell of hundreds of workstations with files scattered all over the place.

The capacity difference between the two cells is not
as large as the Amp-hour rating would seem to indicate.
Li-ion cells operate at about 3.6 volts, while NiMH cells
operate at about 1.2. Thus, assuming constant voltage
during discharge and zero internal resistance (incorrect,
but it makes this easier), you can calculate capacities of:

1.2V * 2.2Ah = 9.5kJ for the AA cell and
3.6V * .53Ah = 6.7kJ for the Li-Ion cell.

Given the higher energy density per mass of Li-Ion
cells and the form factor flexibility ditching the
AA provides, this seems like a good tradeoff.