You buy the kit for around a thousand dollary doos and you just basically bolt it do your hub and in the fork and voilá, you made your bike into a long john. It even comes with some nifty thing to change the brakes from normal to cargo bike. Holds up to loads of about 150lbs in the box there.
I think it's a pretty cool concept from an enviromentalist standpoint because you can retrofit any of the million currently existing bikes without having to produce entirely new ones.
If you only occasionally could use a cargo bike switching from one thing to the other takes about 5 minutes apparently so storage is easier even if you don't leave it permanently attached.
They just need to figure out a way to include an e-drive here, as it is it's basically for young, fit people in flat areas as it stands, allthough seeing as it already integrates into the hub it feels like a problem that could be solved.
I'd argue the clunker'll run you up more costs than the extra for a new cargo-bike fairly soon, but there is absolutely a problem with the pricing as it has to contend with cars, but without any of the massive subsidies, which makes them comparatevely expensive.
Some states and municipal governments here in deutschland have started to offer to chip in, usually at around ~30% to 40% of the listed price, capped at between 500 and 100€, which at least helps in some regions. What you'd really need is one or two federal subsidy programs to really kickstart making production via largely automated assembly lines viable so the price goes down.