A buyout only works if one spouse can actually refinance in their own name for the full remaining balance plus the equity owed to the other person, and many lenders require that qualification to be confirmed before either spouse signs anything final.
Selling on the open market avoids that financing hurdle entirely and produces a market-tested number both spouses can rely on, rather than an internal appraisal one side might feel undervalues the home.
A lawyer handling the file will walk through both paths with the actual numbers before either spouse commits to one. Get your hand-reviewed valuation from Joel Dyck.