Not really. I disable camera access to most apps on my phone and in general I trust that. Never felt the need for a physical shutter.

I think if I was in an environment where I used my devices within eyeshot of others frequently I’d probably think about a privacy screen protector, but I typically have private places I can use my phone for sensitive things so I just try to be cognizant of my surroundings to prevent shoulder surfing

All depends on the threats you’re concerned about I guess