[Reubensson]

I think you need cookie banner only if you use non-essential cookies. For example if you use cookies only for user auth, you don't need to display any notification about that.

[ID1452319]

My understanding was that you need consent before storing or accessing information on user's devices.

[detaro]

No, Reubensson is correct. The rules for what is essential are generally fairly strict, but only non-essential needs consent.