This person is asserting that the market for Bitcoin is a great source of liquidity.* This is patently untrue; it's well documented that dollars and access to banking (and thus liquidity) are scarce in the Bitcoin/cryptoasset ecosystem. This has necessitated Tether and other stablecoins, to enable trading in the cryptoasset ecosystem without losing dollars from the ecosystem, or wiring money into and out of the unbanked exchanges.

I think the subtext of this particular response to your question is also that Tether is a buck wild part of the cryptoasset ecosystem, being the people in whom the most trust has been placed, even though they have been repeatedly demonstrated to be lying and have obvious and severe conflicts of interest, and it's just a crazy rabbit hole and systemic risk that ought to be discrediting to the ecosystem as a whole. But time and again cryptoasset folks will roll their eyes and say, "This again?"

I'm frankly not interested in taking the time to cite any of this, but if you throw Tether into the HN search, there are many, many credible takedowns of Tether.

* At least, this is how I interpret "store of liquidity," liquidity isn't something you store? It's the property of a marketplace to execute trades readily and at a low cost? So this may be some jargon from the cryptoasset community with some alternative meaning.