I literally don't know anyone who has used the UNITY version of Vocaloid, but I have heard it is much more difficult to use and is a stripped back version. I strongly believe those who aren't used to programming probably aren't going to be able to use it (there is no piano roll/interface, YOU have to program one).
This is a video (timestamped) about info on Unity with VOCALOID (ends at the 27 min mark):
He says what it is used for and the bad things about it, includes demonstrations (her voice quality is
significantly worse than normal in the Unity version).
Wiki page containing extra info about Unity with VOCALOID:
Unity with VOCALOID is a version of the VOCALOID engine built for the Unity Engine, similar to how the software was adapted previously to create VOCALOID Editor for Cubase for the Cubase software. It was released sometime in December 2015. The software acts as a plugin for Vocaloid, allowing it...
vocaloid.fandom.com
I couldn't find any blogs or anything like that made by English or Japanese speakers explaining how to use Unity with VOCALOID, and the only videos I could find are shown in the video I linked to.