By stringing the boxes together and attaching them to solar panels of varying size, shape, make, model, etc, an end user can create a solar array of their own design. For outdoor use they'd use waterproof cables that match the USB socket standard.
They could set something up that works in their back garden, on their roof, on their porch. Hang it out the window of an apartment. Something that folds up. Something that hangs off a bicycle. Something they can deploy on a camping trip, to charge their crap and their car battery in an emergency, then roll up. Spend a hundred bucks on a panel, then next month or next year spend a few hundred more.
The key is, the boxes can be daisy-chained from one panel to the next in as long a sequence as needed, or in a tree pattern using the one upstream socket and the two downstream sockets. Attach a battery anywhere on a node and it will charge the battery when it can, then draw from it if it needs to. It's an ad-hoc power grid that any reasonably intelligent ten-year-old could assemble.
The trunk node snakes inside the house and goes to a box not unlike a UPS that spits out normal household 110. The big power spikes get handled by the normal power line, but everything is assisted by the battery-backed input of your trunk node. Give it an 802.11 chip and some clever firmware and you could monitor the whole tree from your phone.
So basically, a little at a time, I could casually construct my own household solar power solution, tailored to my budget and my terrain, and scale it from "let's charge my phone" all the way up to "let's dry my clothes and charge my electric car" without interruption.
Who is working on this?