My grandparents did during their final years

I say there is no single answer - do what works best for you and your partner - for me I think I'd be into it, I'm thinking about getting all hot and sweaty under the sheets and not in the good way

I don’t have a problem with it. You’ll get a far better night’s sleep if there’s no one snoring their head off/feeling like a furnace/constantly moving around next to you. If you’ve slept well you’ll be a lot happier and full of life the next day. Also, if you’re the type of person who can only copulate while lying on a bed during the hours of darkness, then separate beds might help spice up your unimaginative sex life.

Whatever works for them, though I wonder how close they really are emotionally if they're sleeping in separate beds. Maybe the spark has died. And yeah, of course there are sometimes specific reasons people want to stay in separate beds, like one of them snores too loudly, one needs a firm bed for their back and the other needs a soft bed, etc.