Yeah I've been messing with some of those apps too. What really helps me is humming the main line first, then going back and trying the harmony suggestions one at a time. I found it guesses chords better if you keep your hum really simple and on beat. Sometimes I'll even record a bad take on purpose just to see what weird chord it suggests, and that actually sparked a cool idea last week. The big thing is it lets you catch a melody before it flies out of your brain forever, which is half the battle. Lets you stay in that creative zone instead of breaking out the old notebook and trying to remember what you were just whistling.