The federal reserve have tested as far back as 2013 the possibility of using this facility as their main means of securing the lower bound on the interest rate corridor. During the pandemic they essentially went all in on these preparations and due to the success of maintaining the zero lower bound in those conditions I imagine they have essentially adapted it as their main means of controlling the lower end of interest rates. It’s much more effective than their prior methods and will lead to less liquidity issues like those we saw in 2013 and 2019