I think that when it comes to "trivial" edits, it depends on the situation. The chief problem with trivial edits is that they fill up space on the main page of questions that could otherwise be filled with exciting new content. But there are plenty of times when this factor will not really be an issue.
For example, if you are posting a new answer to an old question, the question will get bumped to the top of the main page anyway. Making trivial edits to the question and existing answers causes no harm because it is not going to put the question in a place that it wouldn't be anyway. So if you are posting new content, I would say you should specifically look for trivial edits to make so that you can take care of them all at the time when they will cause no harm, rather than leaving them for someone else to potentially take care of at a time when they will cause harm. Indeed, as I am posting this answer I would have made a one-character edit to Tinkeringbell's answer if I had enough reputation (it's fewer than 6 characters so I can't suggest it), for this very reason.
(If you do this you should probably do the edits before posting your new answer, so that the last activity shows "answered by" instead of "modified by" and links directly to the new content.)
Similarly, if you are making significant edits to an answer, you can also add trivial edits to all the posts on that page (i.e., the question and all the other answers), since, as mentioned, it will not cause any bumping that wouldn't have happened anyway.
You can also do something slightly reversed of the above. If you see a trivial edit that you want to make, you can try to find other things to edit that are less trivial. Very often you can find other things that can use editing, either in the same post, or in one of the other posts on that page (i.e., the question or any of its answers).
Another instance where the downside of trivial edits is severely limited is when the question has a very negative score. Questions with very negative scores don't appear on the main page even when edits are made, or even when genuine new content is posted. As such, I think it is much less of an issue to make trivial edits to a question (or any of its answers) that has a sufficiently negative score that it will not appear on the main page. (e.g., this very question does not appear on the main page because it has a score of -8.)
Finally, I think there can be a distinction between making trivial edits to your own posts vs. making trivial edits to someone else's posts. When it comes to someone else's post, there is the downside mentioned above, as well as the fact that the post owner may not appreciate it and may even actively resent it. However, when it comes to your own posts, I think you should have greater freedom to make trivial edits. If there is a spelling or grammar mistake in something that has your name attached to it, I think you have the right to correct it, even if you do not add any additional useful content. Of course, if you can add something useful — as per above — that is certainly better.
There have certainly been times when I have made very minor edits to my own posts, yet have not made similar edits to other people's posts. I don't want there to be anything attributed to me with mistakes in it, so I will fix them. Other people might not care about that, and I think that is their prerogative.