Is it wise to divorce one's spouse, yet continue to be married, for financial reasons mostly and to qualify for benefits if needed?

There is a thing (for lack of a better word) that is sometimes called "financial separation". No divorce. BIL did have to get rid of the nephews car since BIL was co-signer on the loan. (I think BIL may have been making payments) And nephew did not work and had no license due to a DUI. I don't know much about it but it worked for my sister and BIL.
It took an attorney to draw it up and get medicaid approval and help.
This was in Illinois.

It’s really not necessary because if one spouse needs benefits, the other spouse will not be left impoverished.

If you are doing this because your spouse may need Medicaid in the next 5 yrs, run it by a lawyer. If this is the reason, the Community spouse will not be made impoverished. Assets will be split with the Medicaid spouses part being spent down. There is more to this but that is basic.

Absolutely That way you take 50% of everything which govt can’t touch. Also you can continue to live under same roof and probably be paid as caregiver. Have separate rooms and either pay nominal rent to the other. Treat all bills as if renting shared accommodation Get separate wills done with his nominating you as POA. But be careful. If this is strictly for more money and not because one has become ill you will probably separate and be much worse off