Lower rates bring in less NEW offshore fiat because there's less yield to attract them. Its an equilibrium of diminishing return, not a signal of weakness, since the rates can only be low if the dollar can command it in the first place... like everyone wishes they could get 2% risk free on Bitcoin

Correct the fed doesn't control the long end, but the funds rate on the short end trickles out because its a multiple of cash in the system to bid those rates, and short term bills are effectively cash in moneymarkets etc.

I think the stables are how they get people in other countries included in what is effectively the US money market, even if the foreign government doesn't like it.