I don't know if there's an official term, so I call it the vocalsynth genre, which includes things like vocaloid, UTAU, deepvocal, enunu, diffsinger, etcetera.
One thing I love about it is that they- especially utau because it's free and there are a lot of voicebanks, tutorials/guides, and other things designed specifically for it- allow you to be able to create a song that would normally never be made by a famous or up-and-coming singer. At least the vocals, though, because you still need to make the backing track (or outsource that to someone else). It kinda evens the playing field when you have people who are not good at singing making songs/covers that are just as good as songs from the music industry.
Plus, there are so many original songs out there and usually covers of said songs that if you don't like one version, you can always find another version that might sound better. That definitely holds true for the biggest songs and even various lesser known songs. All the songs are made from people across the globe, so you end up with a lot of different songs of different genres, themes, etcetera.