You can use a static-switch parameter, but you have to be careful with how you use those else you could make too many path-permutations and create a great many shaders from just one graph.
Generally speaking, less is more. Just having a node that is used has overhead, so even if you sample from a texture 1 time, just having it exist in the material has a cost in and of itself. This is why packing is valuable as you can carry that cost of the sampler across x-samples.