Point is that tracking isn't the only thing that's not "strictly necessary". And additionally that "strictly necessary" is tied to something specific: internet society service. That includes a very specific requirement: "Normally provided for remuneration". That's why e.g. public authorities should not (usually) be allowed to rely on it, public services are not often provided for remuneration in EU-law sense.

It also limits the exception in relation to e.g. employment.