Yes, Scientific Enquiry is eminently useful, as is logic. However, so is Newtonian Physics.
Newtonian Physics is also, technically, wrong.
Philosophy is there to give you an answer late at night when you finally realise you can't prove that 1+1 =2.
Actual example.
Now, with my tongue entirely out of my cheekpad, I would say that the actual purpose of philosophy is to guard against the Socratic fallacy - the belief being an expert in something gives you the right or qualifications to speak on any and every topic.
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