Large swaddle blankets make great car seat covers while baby is still in a bucket seat, or they can be used as a stroller cover when baby takes a nap on the go. They’re nice to put on the floor for tummy time (although you can do this with literally ANY blanket, and if you have hard floors, you’d probably want a thick blanket instead. Swaddles are usually a thin blanket.).
Of course, they CAN be used as burp clothes if you need something to dry off in a pinch. All around, they’re good to take with you if you’re leaving the house with a newborn. I used mine as a nursing cover for breastfeeding in public, and my (now bigger) kids regularly use my good aden+anais muslin swaddles as super hero capes now that they are older. So it’s not like they’re just gathering dust just because we’re done swaddling. LOL.