I'm surprised at how often this needs to be restated.
By-and-large you only need to allow people to opt out of cookies if you're tracking _their_ activity and/or selling details of _their_ activity to your "partners".
Partly it’s because we’ve simplified the discussion to “cookie banners” when it’s about more than cookie tracking or cookie-like tracking (local storage). So it misses all the other ways tracking occurs.
The other thing is that it benefits those who wish the law would just go away to have it misunderstood this way.
By-and-large you only need to allow people to opt out of cookies if you're tracking _their_ activity and/or selling details of _their_ activity to your "partners".