Why it would be useful for central banks to buy equities during recessions

Share purchases by central banks , which only a small number of them are involved in (Japan, Switzerland), would be an effective economic policy instrument: Obviously by lowering the cost of equity financing ; Also by creating a positive wealth effect; But, what is less often mentioned, by lowering the cost of capital for banks, which in turn lowers the cost of credit ( 1) . See, for example, in another context for this positive effect of the fall in the equity risk premium: X. Liu, S.J. Wei, Y. Zhou "A Liberalization Spillover : from Equities to Loans" NBER Working Paper no. 27302, June 2020