Though I am curious what your definition of widespread adoption is. I think it is important that we are realistic about what widespread adoption means in cryptocurrency, especially an altcoin in the current market. I can see a world where my mother uses bitcoin. I cannot see a world my she would use any altcoin, unless a major feature/change/disruption is released of a magnitude 100x what we have already seen from all alts combined, I don't see that changing. I do think there is a very important market for altcoins, much greater than day trading and currency speculation. And it is a market I am invested in, with a very significant amount of my time, and to a lesser extent, money (more if I could afford it). And it is that market I look to when I am considering the widespread adoption of the coin, because realistically widespread adoption in terms of the general public is at the moment still questionable for bitcoin, let alone an altcoin.
"Widespread" is a relative term -- better to think about it in terms of a direct comparison: which approach do we think will result in the larger market share long term?
I do see your point, but I think we share a fundamentally different viewpoint on where altcoins are going. I don't see mass public adoption even a remote possibility, not .000000000001%, in my mind it is 0.0%. (Though I do just want to make sure I am clear here, I don't think altcoins, specifically darkcoin, is worthless, I think they have some great potential and will continue to have value for years to come. My mother just will never use them for example.) At least not without the kind of major improvement I described above.
Given that viewpoint, long term, marketing in terms of the general public will be the less successful route.
But if I am wrong (which all it is a guess, hardly even an educated one, because the events leading to or away from mass adoption will likely be unpredictable chance occurrences rendering any "educatedness" of the event moot) then a marketing scheme more towards the general public absolutely would win out.