Self-votes are an issue on this platform, but there are various nuances we can think of.
It's one thing if you upvote mainly yourself, it's another if a low percent of your total upvotes' value goes to you.
It's one thing is if you are a whale who can influence the reward pool drastically, and another if you are a plankton or a minnow.
It's one thing if you have delegations to run a service, which return profit to delegators (bidbot, for example) and self-vote, it's another if you run a community account with delegations, which will upvote members' posts based on certain criteria, and which also upvotes posts created on the community account.
And I think we can find more such distinctions.

Source
Since I started on Steemit, I upvoted my own posts, but have not upvoted my own comments. I know people who do the vice-versa, not upvoting their posts, but regularly upvoting their comments (at least for visibility). And, of course, there are those who do both.
I think none of these practices are bad if
- they don't have a high influence on the rewards pool or the posts rewards toward the end of voting period
- the percent of upvotes' value that goes to the community is much higher than that of the self-votes
- they don't self-vote using delegated Steem power which is expected to have a return on investment (bid bot style)
But something not being bad doesn't make it best either.
For example, if I start with the habit of upvoting my posts when I'm a minnow, I will probably continue the same practice as a dolphin or, to dream with the eyes open, as a whale.
Now, my 5-10 cents upvotes are not really so impactful (not even to myself) as full dolphin, but mostly whale upvotes.
So, it's better to cut it while it's green. :)
In fact, the rationalization for my self-votes don't really stand at closer scrutiny. I thought they are a way to say I value my own time (to write the posts). But if that's the value I put on my time spent to write these posts, then why should I expect more from anyone else, ever?
So, I made the decision to STOP upvoting my posts, and continue not to upvote my own comments (maybe I'll make an exception on this when visibility is important).
I will continue to upvote all non-spam comments on my posts.
Going forward, roughly 10% that were my self-votes will be directed toward the community, which will get 100% instead of 90%. Will it make a difference? Probably not much of a reward-wise influence for the community, but at least I won't have this to hold against myself if I will ever doubt my involvement.
Steem on!