High public debt efficiently channels tax dollars to rentiers through their very low-risk bonds. It implies some dependence of the public sector on rentiers. If it reduces capital formation, it makes existing capital more scarce and providing of higher returns. OTOH, by propping up interest rates, it denies capital gains to bond-holders, whose holdings would increase with a rate decrease. It also raises borrowing costs to non-financial corps.
Interest rate drops jazz up the capital markets.
Low public debt flushes capital into private capital markets, the better for traders to skim in a more volatile environment. Also a source of more transaction-related fees. In the present context, elimination of debt sets the stage for Gov accumulation of financial assets. The potential implications of Gov ownership from both left and right perspectives are obvious. The balance of interests at the top clearly favor less debt rather than more.