If you take those smaller boxes and start walking them into other parts of your ship to try to cram in even more than your cargo area holds, how does that work?
TL;DRLoose boxes carried elsewhere in the ship still count as cargo and can be sold but can be stolen; purchases now take at least one SCU slot, so mixed small quantities quickly exceed capacity.
You can sell it. It's still part of your ship, and so whenever you land it at a station, it still shows up as part of your manifest, but they're loose, so that means, again, they're not locked down tight. Someone can walk in and steal them. So yes, it's still cargo. That said, there was a bit of a change since that video went in, again with the previous cargo change I mentioned, where when you're now buying cargo, it's always going to occupy one SCU slot at least. So if you, say, buy eight units of agricultural supplies, that's going to occupy one cell, one SCU box in your grid, and so you can keep buying and fill it up as much as you want until you hit a second or a third. But you can't, say, diversify and buy one unit of every single different thing, because very quickly you're going to exceed the physical capacity for your grid to hold it. So it makes you kind of have to invest in a particular commodity if you start buying into it.
Because the boxes don't mix. So you can't have one unit of this...
You can't have, like, half and half.