In disruptive industries people wear many different hats, and it is common to simply ask the 'web design guy' to do a bit of growth hacking for the company. It doesn't mean they now become a full time growth hacker; it just means that visitors need to convert somehow, and some design skills can achieve that. What annoys me is when an employee is called a growth hacker on the company page or wears this title like a badge of honour. All employees can do a bit of GH on the side, but it should never be a full time position IMHO.