My only experience with any sort of auto-tune is briefly testing Slate’s MetaTune. I assume free Autotune is similar in that you just select a scale and drop it on a track and it quantizes any pitch to that scale well enough. For a lot of uses, I see the reason you’d use that - a full version of Autotune/Melodyne is several hundred USD compared to a free/cheap version, and the cheap version is “close enough”. Also could make sense for a demo track or something where you plan to have it produced by a pro later on, but you need a rough idea of what that will sound like while you write the track.
Frankly, for a lot of electronic music, I think full Melodyne is a bit overkill as we’re already working with such processed vocals, vocoders are an option if we want perfect pitch, and the stuff that full Melodyne gives you access to versus the free Autotune is basically more of a word-by-word control of that pitch correction that you might need a handful of times throughout a song. Take my opinion with a grain of salt as I think I have vocals in one track so far, so it’s not my expertise.