@Chris15824 Sounds smart to replace the sliding shutters- for sure if something is a bit fussy to work, guests will inevitably break it.
Even though no one can "stand and see in", I would use a covering. There are houses I see in the photos where conceivably someone could use a pair of binoculars and see in. Not that that is at all likely, but you have to consider guest perceptions and possible paranoia. I could imagine guests having a sex romp in the living room and feeling exposed. And they might want to nap on the couch and cut out some light. Or cut the glare on the TV screen or their laptop.
It doesn't look like it would be hard to put up some curtain rods and simple curtains. Make sure the rods extend far enough when the curtains are open that it doesn't block the view at all. And make sure to mount the rod supports at the ends of the rod, so the curtains slide all the way back.
I've read several posts over the years where hosts didn't think the windows needed coverings, because no one could see in, but guests complained about it.