in some situations it would be more advantageous to file separately, but it depends on the specifics of each person. Fore example, if one of you has very large medical expenses with a small income, those medical expenses could exceed 7.5% of that person's income and be deductible when itemizing where if there was a joint return, they would not be deductible.
however, assuming you own your home jointly, why are you not each taking half of the mortgage interest and property taxes? Given the SALT limitations, it could skew your results by one of you taking all the property taxes and one taking all the mortgage interest. (this is where a CPAs advise is helpful). How would you explain to the IRS why you did it that way and it is supportable by the IRS requirements?
you don't state how much of the benefit is driven by federal and how much is driven by the state in which you reside. And you don't mention which state. That would be interesting for this forum to understand. Maybe the state you live in is driving this phenomenon?
bottom line is that your question can't be specifically answered without a thorough review of your circumstances.
