I got one of these a while ago, and it'll be a back up, keep in the car, sling, most likely.
They do offer 'size insurance' for just a few dollars, which might be a good idea for anyone taking them up on this offer.
The slings are a single layer of cotton, and seem 'light duty'. I've made lots of carriers, and all of mine seem more 'every day use' than this one does, so that is why it'll likely be a back up! That said, b/c it's only one layer, and not thick, it folds up really small & will be easy to tuck in a glove box, handbag etc.
For a 'free' sling, it's not bad! But I'd never pay full price for it :)