Regardless of what their motives are, the chief role the Libertarian Party plays in national politics is making the two-party duopoly (even the current GOP!) look legitimate by comparison, and serving as a constant reminder to the public that third parties are a sick, sad joke.
American third parties are clown shows because 99% of the country is constantly railroaded into choosing between one of two options, and the only remaining 1% are hardcore ideologues who think "compromise" is a four-letter word. If the Libertarian Party were given an actual chance in a fair, ranked-choice voting system, it would quickly move towards the center, attract more voters, and expel the nutjobs who are currently associated with it.