You always need these swaddles!
Today, the swaddles are mainly advertised to wrap babies in them tightly, or to 'swaddle' them. (There are plenty of instructions online). The firm 'cocoon' gives baby a secure feeling of support and security.
It used to be cloth diapers or 'burp cloths', which is really not a nice word. But the word, or the name for it, is irrelevant. In fact, they are the most important utensil that you should always have with you.
So that nothing goes wrong with baby's tummy, or for everything else. Babies stain and you need a cloth like this anytime, anywhere.
Also to use it spontaneously as sun protection, or as an additional blanket.