The phrase "to blur the lines" means to make something become less clear or distinct. It is often used to describe situations where boundaries or distinctions between different things become unclear or ambiguous. Full definition
The only reason I say this is because, to say that a tablet might «make a good e-reader» kind of blurs the line of why e-ink is preferred over lcd screen (refresh rate and front lit light). (goodereader.com)
However, in spite of what Apple says now, the company is studying the possibility of further blurring the lines between iOS and macOS. (bgr.com)
These abstract works blur the lines between painting and photography — and if electricity had a color palette, this would be it. (artsy.net)