> In practice though tax cuts usually make rich richer without helping the economy to grow (because of lobbying/corruption).

This is being generous. It's much simpler.

The poor don't pay any federal taxes at all so you can't give them a tax cut because they don't pay any. You can give them a credit at best.

Edit:

Some data

> Another 60.3 million returns showed AGIs of less than $30,000. The average effective tax rate for those taxpayers was 1.5%, even before refundable tax credits were applied.

From: https://www.pewresearch.org/short-reads/2023/04/18/who-pays-...