So, in the absence of a way to gut the SS trust fund faster by ending the return of SS income taxes back to the SS fund, they figured out a way to accomplish the same result with an extra benefit of short term fast wealth transfer instead of longer term.
It is a bit hard to explain what I am seeing. Money collected from taxation of SS benefits is returned to the Social Security system and either deposited in the trust fund or, when the trust fund doesn't have enough to cover benefits, used to pay current benefits.
Any change in the tax on SS benefits or change in the standard deduction for over age 65 or change in the tax rates affects the amount returned to SS.
The links below discuss the result of the Committee for a Responsible Federal Budget (CRFB) calculations which found that the OBBB and ending taxation on all SS benefits reduces the "solvency" of the SS trust fund by one year.
OBBBA Would Accelerate Social Security & Medicare Insolvency
Donald Trump's Suggestion to End Taxation of Social Security Benefits
I might add that who, among the over 65 crowd, benefits from lower taxation is different for the two schemes since the end of taxation benefits everyone paying taxes on their SS. The OBBB doesn't benefit tax payers above the income caps.