As is the case with many questions regarding legal matters, this depends on some different factors. It is more simple to name your spouse directly, and your spouse could then convert your retirement plans to their IRA and take withdrawals on their schedule.
That being said, trusts have a number of advantages. Trusts can provide a lot of protections, including greater creditor protection compared to retirement funds, protection in the event your spouse becomes incapacitated, protection from scams (as seniors are often targeted), and protection of assets from having to be spent paying for long-term care. They can also preserve funds that are not needed by your spouse for your children.
Trusts can also be a useful estate planning tool. As the threshold is just over $12 million, most Americans don’t need to worry about the federal estate tax. However, many states have their own estate taxes, including some with the threshold as low as $1 million. A trust can protect this amount from being taxed following the death of the survivor of yourself and your spouse.