Then my point stands, because you could have withdrawn $50K in cash, if you had that much available, and had $50K working for you all year, rather than using it to pay interest and getting back $20K cash to have $20K cash working for you...
You still can keep your $50k cash and/or have it working for you, plus an additional $20k increase in cash flow from tax deductions brought about by pre-paying the following year $50k interest bill using borrowed funds.
You still have your $50k plus another $20k.
Capital & debt are 2 sides of the same coin.