My kittens never did chew, fortunately! Scratch, yes, destroy the curtains by running up and down them, absolutely, but they seemed to know what they could safely do.
I didn't really care if they (or my dog) damaged the furnishings, as long as they didn't hurt themselves, but my dog when he was a pup he didn't have the same sense of self-preservation as my cats, and had to be trained not to chew things.
My husband didn't work so was around for our pup all day but it's unrealistic never to leave a puppy unattended for short periods, e.g, while having a shower, and, indeed, they need to learn gradually to be left alone if you don't want to end up with a dog that has separation anxiety. So we used the crate for short periods during the day, and overnight.
By the time our doggie was 'grown up' he was happy to be left for a morning or afternoon when needed, because we'd built up to it, starting with literally a few minutes, and he had the freedom of the house by then because we'd been able to train him to know what he should and shouldn't play with.