the fan would probably be a restriction when it's not on though (because of the big bit in the middle that doesn't flow air - the electric motor). And if you are not traveling along fast enough for air to be rushing through the scoop then your turbo isn't going to be generating enough heat to raise your intake temps further, so it will just cool down by itself - this is probably the thinking of Subaru over many years or else they'd probably mount one.
I do think it would be beneficial if you like doing static burnouts or heli's lol

It's funny ppl always rekon they know better than the manufacturers, like fitting a manual switch to radiator thermo fans when they are automatically controlled anyway!