When I'm strumming & singing with a group, my voice doesn't sound half bad, for the most part. But let me try to sing for an open mic and my voice seizes up like crazy. My vocal range is already limited, and throw in some nerves.....well it ain't pretty. I'm working on it, just like everything else. That's why I enjoy chord melodies. It's kind of like strumming chords and playing the single note melody meet somewhere in the middle and sound great. People know the song I'm playing, without my vocals making a mess of it, and it sounds lovely. At a recent jam, I played chord melody for "Bridge Over Troubled Waters." I asked the group to sing along softly if they felt the urge. About 25% of the group (the usual awesome singers) joined in. Their singing was beautiful, and it didn't overpower my playing (I was plugged in), but rather enhanced the whole thing.
I've written two original, but simple chord melodies of my own. Sometimes a chord progression just strikes me, and I start building a melody that I like. It's fun to experiment. It has encouraged me to play up the neck more, look for 2nd and 3rd positions, different fingerings.
Do what makes you happy is the bottom line. As Jerry put it so well above..... There is no such thing as wasting time while playing your ukulele.