Each disabled token is pure profit to Tether. They're not cashing them out to the US Treasury, as with Bitcoins recovered from criminal operations.
It's an interesting question: What does that mean? Maybe it's better to look at cryptocurrencies as financial securities, shares in an asset controlled by a private company (as has been said many times before). Could General Electric 'disable' the shares of a shareholder? What would that mean? The shareholder can't sell their shares, I suppose, but GE's equity would remain the same (not counting any market movement t…
When coins are lost, they stop circulating; that amount - of active, unique coins - is the M1 value, or the amount of circulating currency. Just like if you burn a key, or mint or destroy a trillion dollar coin thats in the Reserve, or disable shares, the value is derived from the scarcity of the resource.
Technically the "uncirculated" money has value, but only as "capital", as it's generally a liquid asset or borrowed against collateral. Uncirculated currency and coins are generally just a very flat asset, just eroding by inflation.