Since controlled fusion isn't mutually exclusive to using Dyson Spheres, why not use both? It seems that constructing Dyson Spheres can only add to the amount

Since controlled fusion isn't mutually exclusive to using Dyson Spheres, why not use both? It seems that constructing Dyson Spheres can only add to the amount of energy that an advanced civilisation is capable of harnessing even if they're also using controlled fusion, so it wouldn't be surprising if they used those unless their energy needs were totally satiated by controlled fusion (or some as yet undiscovered alternative source)