Personally I do not see a problem with self voting one's articles that are quality. Of course, this is subjective. However, if one takes the time to put in effort into an article and the person thinks it quality, an upvote is warranted.
I do not upvote my comments. Comments are made in response to the author and belong to that person since it is his/her article. If the author and other ones commenting thing my comment worthy, then they can upvote it.
Just my .2 steem.
There is no advantage to that.
10 accounts with a $6 vote in each is no different then 1 account with a $60 vote.
Splitting the SP across all those accounts does not yield any advantage in that regard.