I've used many different techniques over the years for reheating food without any loss in taste or texture. After I bought my foodsaver, the "vacuum" and heat in water" is the best way, wins every time. Sometimes I crisp skin and so on with a small gas burner afterwards.
If it is "sous vide" or not- can't care less. It works every time.
Some time ago I mentioned this to a professional cook, and he told me that this process has been used in restaurants for ages, long before sous vide cooking became trendy.