I really try not to "content-shame" developers, but the ratio of "media" to hard drive space feels a bit skewed. Over 7GB? And no animations or sound effects (unless I missed them.) For 7GB I'd at least expect the characters to say their few dozen lines out loud. Or blink. Not sure what benefit the Unity engine is providing either. But OTHER than that, fun "little" game.
Unity can do current-gen stuff. Renpy is still stuck somewhere around the nineties, with a 2015-ish framework.
Renpy is made for visual novels and nothing else. It's made to display (simple, low resolution) pictures and no video basically. People found ways to handle that, but it's not really supported by pygame (for modern use) which is what Renpy is driven by.
Unity can do everything and more. You can even integrate 3D in visual novels.
Also, renpy doesn't natively compress media, which Unity does on demand.
If you do the same "Hello world" test in Renpy and Unity with fx Naninovel or UVNF or Fungus, with the same graphics assets, you will end up with a project taking up at least 50 MB more in Renpy than in Unity.
Renpy also is not compiled, meaning it is considerably slower both at startup and during the game. One thing is that Renpy has to load complete artwork before beginning to display it, that includes video.
And, as someone else mentioned, Renpy won't ever be able to do anything advanced. It's variable system is also limited.
In general, a developer should try to get familiar with fx Naninovel (which in it's text based language is even easier to use than Renpy).