Storage gaps and ERC-7201 namespaced storage layout are two different ways of allowing base contracts' storage variables to be added to in the future without affecting child contracts which inherit it. ERC-7201 (if all of your contracts are using ERC-7201 instead of storage gaps) additionally has the benefit of allowing inheritance order of base contracts to be changed, without affecting the resulting storage layout.
If you don't intend for your Distributor to be inherited as a base contract from other contracts, then it is not necessary to include a storage gap. But it is fine to do so.