Very practical IMO. The wind up alternative requires CONSTANT winding, and winding in and of itself is a rather aka ward motion unless the item is mounted on something (which it couldn't be if you had to constantly crank it, thus had to walk around with the thing to use it).
Let's pretend you have an unfurnished basement you use as storage, perhaps you actually do. With one quick easy lift, you can have light for the entire duration of your time spent in the basement looking for whatever it is you need to bring upstairs. You don't have to bother turning it off on the way up while your hands are full, it'll turn itself off when it finishes falling, and it doesn't have any impact on your electric bill. You always know exactly where it is, as it doesn't move, so there is no "fumbling around in the dark", it becomes just as natural as flicking that light switch in your bathroom in the middle of the night.
See? A totally practical use right here in our electric-powered homes
. Now imagine how many times more useful it would be in nations with unreliable/no power grids.
Besides, lets face it, most of you users of this forum could afford to lift a small weight a few times a day