I think having consumer-readers is inevitable if your comic is to grow big enough to replace your day job. On Naver, most (if not all?) pro comics have "cafes," which are fan-run community forums, and from what I've seen, the environment in the cafes is much more supportive than in the comments section. So that helps. LINE doesn't have that though, which is too bad.
Tapastic would be VASTLY preferable. One positive I have to say about LINE, though, is that they're very actively advertising their comics, both internally and externally. Externally, I always see their ads on sites like gameFAQs. Internally, their pro comics get a TON of exposure.
I don't see Tapastic doing external advertising (though I don't know if the way LINE is doing is the right way to do it), and even though top creators on Tapastic might be making a sustainable amount of money from the support program and the ad revenue combined, YOU have to get there yourself, unlike on LINE where if you get picked, you get auto-exposure.
While I listed those as "positives" for LINE, that doesn't necessarily mean that not having those features are "negatives" for Tapastic. They are two very different approaches, and while LINE's method has been proven to be effective in the Korean market, the Western market is very different and may require different methods. Whatever the magic formula is, I'm hoping Tapastic is close to figuring it out. :] Wishing best of luck to the Tapastic staff and to all my fellow creators here!