Wearing a kippah is about a baseline. It isn't so noticeable in itself, but it means that taking it off is a signal to yourself. Taking it off, or disguising it, means that what you're doing is likely to be questionable.
Sometimes, questioning it may yield the answer that you're answering to another Jewish value that makes doing something that is halakhically marginal appropriate (for example, going into a non-kosher restaurant to be with your family).
Sometimes, it turns out to be a reminder that actually, this isn't a good choice.
But either way, without the baseline, you don't have the reminder. It makes an awareness of other people's gaze into a reminder of God's gaze.
What message does your kippah (or devotional head-covering practice) send you?
How do you feel about it?