The question was raised by a reader (welta), why divorce in lieu of legal separation?
This is my best guess as to why she and her advisers chose this route:
"Unlike divorce, a legal separation takes effect immediately after it is ordered."
"After you file for divorce, you must wait an additional six months before your divorce can be final, but there is no waiting period for a legal separation."
Filing for Divorce or Separation FAQs
Q. I filed for divorce, but I have changed my mind and want to cancel the case. What should I do?
A. If you are the 1 who filed for divorce, you can file a Request for Dismissal (Form CIV-110) to dismiss your case, as long as the divorce or legal separation is not final yet.
Bearing in mind that she doesn't really want to be divorced or legally separated, filing for divorce gives her more time to file a Request for Dismissal.