This is an interesting boost converter for motes because most of the time your mote could be sleeping or doing light work with a battery's voltage/current passed directly through to the mote, but on those occasions where you might need more voltage/current than your battery would volunteer on its own, you can have your micro-controller turn on this boost converter. Or perhaps it could scavenge voltage from a super cap that would otherwise go wasted because it was too low. The point is this: by being selective in your use of the boost converter, you avoid the higher quiescent current losses that would come from constantly running a boost converter all the time.

The quiescent current of the LTC3525D is 7ua when active, so you're better off using it only when you need to rather than running it continuously.

Datasheet: http://cds.linear.com/docs/en/datasheet/3525d33fb.pdf