I don't find wheat bags hold the heat anything like as well as a hot water bottle.
We live in an old cold house and I use a hot water bottle for every bed in the house - it's part of my winter evening routine to put them in about an hour before bed.
It's important to check the dates, replace them regularly, not overfill or use boiling water and expel air. But that doesn't mean you can't use them at all.