It's an interesting set of tradeoffs - vtubing has made it possible for people to be on-screen personalities who normally would not able to as easily because it can be very hard to overcome problems with your IRL appearance. That stuff really matters if you want to succeed on YouTube or Twitch. In comparison if you want to be a vtuber, there are relatively affordable ways to grab a stock model and customize it. You can also just commission a custom one from an artist and rigger - though I think the cost of that is sadly out of reach of an amateur it's not as high as you might assume.

If you stream without a face camera at all it generally hurts your ability to grow an audience, and unfortunately our society is still pretty focused on appearance so if you don't look great you're going to potentially get a lot of toxicity in your chat. A vtuber avatar acts as an equalizer in this sense and also lets people express their personality and aesthetics visually in a way that might not otherwise be easy - they can pick eye and hair colors they think represent them without having to use colored contacts or hair dyes, etc.

A few different people I know found that having a vtuber avatar made it much easier for them to get into streaming regularly and it did grow their audience, so I'm happy to see the technology catch on and improve.