I tend to use "uncertain" under two conditions - one is if I'm using {{DateGuess}}. In that case, your proposed alternatives would also work. The other is when I have conflicting evidence, especially if there's a big difference. For example, if I have data from 4 consecutive census, where the age varies wildly from census to census (and I'm certain it's the same person), I'll pick on (usually from the earliest census, unless I have reason to believe a different one is more likely), and I'll mark it as uncertain, and put a note that it could be anywhere within a range. In that case, I have sources, but the date is still uncertain.
Generally when I'm creating a new profile, I don't click on either option. Though once you've selected one, you can't change it to nothing.