> He uses the word "chattel" because it's a term that was used in the slave trade, but he can get away with it because technically it's just another word for "currency".
No, its not another word for currency. "Chattel" is a widely used legal term for personal property; its used as an adjective with "slavery" to specify a particular kind of slavery (the one in which slaves are legally treated as chattel, which while its probably the most familiar kind to most people is not the only thing considered "slavery"), but the term "chattel" itself isn't particularly associated with the slave trade.
More relevant, "chattel currency" is a term for things used as currency that are not legal tender (its not exactly commonly used because there isn't a lot of need to discuss that particular class of things.)
However, there is one place its pretty commonly used, and that's among the kind of conspiracy theorists (often goldbugs) who think (for example) that Federal Reserve banknotes aren't legal tender and are a scam to get you to surrender your "real" money (which these conspiracy theorists seem to think is still real legal tender) for "chattel currency".
Given that a not-insignificant number of those conspiracy theorists seem to have flipped from being goldbugs to "bitbugs", I wouldn't be surprised if it was the use of the term "chattel currency" was calculated, but it certainly wasn't a slave trade reference.
> Some stats from Google search
Counting search results isn't a substitute for knowing what you are talking about. I'm actually surprised that "chattel property" (which is a redundancy) has that many results, but that doesn't change that "chattel" means personal property, and that its use to refer to that is the most common use.
It is also true that "slavery" is a common context in which "chattel" is used as a modifier, and that use -- because specific discussion of that form of slavery as a class is much more common than specific discussion of non-legal-tender currency as a class -- is vastly more common than reference to chattel slavery.
But that doesn't mean that "chattel currency" is a reference to chattel slavery, any more than the fact that "green" is far more frequently used as an adjective to modify "eyes" ("green eyes" -> "about 500,000,000 hits") than "grocer" ("green grocer" -> "about 1,840,000 hits") means that the phrase "green grocer" is a reference to "green eyes".