Suppose a couple made a one employed spouse and one self-employed spouse. Further suppose that the couple choose to file jointly.
Instead of having the self-employed spouse pay anticipated taxes of x$ quarterly, could the couple instead have the equivalent x$ retained from the employed spouse in the form of extra-withholding (provided the x$ are properly spread across the relevant months)?
Take aside what could happen if the couple split up before the end of the year or otherwise decided not to file jointly anymore. Also, suppose that the money that goes to taxes through the employed spouse's extra withdrawal over the course of the year is exactly identical to what the self-employed spouse would have paid otherwise (in the form of quarterly payments).
Are the two above options equivalent from a tax liability standpoint? In particular, could the extra-withholding option lead to penalties, interest, or other drawbacks the quarterly payment option would avoid?