It costs time whenever some coworker asks for something impossible, and says something like "Have you really checked all the options?"
Why do you have team members toggling settings at random at will?
If that's a real problem with your organization, you have far more pressing problems than the number of options offered by a service you consume.
I guess you'd be the type with unrealistic demands.
So, to be fair, yes it costs to not use features you do not need in this case.
You literally pay by the hour to use S3, and you also pay the hours you spend trying to understand the permissions and modify settings, so it literally costs to not use the features you do not need in this case. I'm trying to make an argument, I'm not saying you pay much, but I answered your question, and you do pay, either by time, or money.
Not really. In order to set bucket request metrics not only you need to explicitly set your bucket to be open to the world but you also need to dig down the options to explicitly enable them along with a metrics filter of what objects you cover.
Object versioning is disabled by default and you need to go way out of your way to enable them at a specific level.
You also need to go way out of your way to set another object storage class.
None of these features are enabled by default. You need to turn them on and configure to start using them.
Does it cost anything to not use features you do not need?
Last time I checked, all the so-called niche features were stashed in hierarchical option lists, outside of the happy path. You need to purposely want to dig into, say, file access, bucket access metrics, storage strategies, object versioning, etc to actually get to them.