Simple roller shutters can be pried open or cut. It can be done relatively quietly without much effort. In that case, you need burglar-resistant roller shutters.
I have ONE window without a shutter in the house, and that annoys me already. Unfortunately, that cannot be changed. I would definitely do it WITH a shutter.
And: East can also be nicely sunny in the evening hours. I want to be able to close it then.
If the budget is tight, a roller shutter for the guest bathroom is a wonderful item to cross off. Not only frosted glass protects against prying eyes, but also a simple curtain. If the budget is not tight, it doesn't really matter. If it were an urgent need to have a roller shutter there, the question probably wouldn't have come up.
I personally hate frosted glass, I have some kind of allergy to it :-)....
In my place, I also have a venetian blind in the guest bathroom, I would also take a roller shutter there at your place and possibly a pleated blind as well.