As an artist, I love betas and cheerleaders, and I love betaing and cheerleading artists. (I'm lumping both things here because the same people have often played either one or both in the past and sometimes the help and support they gave me were very similar.) I'm pretty much always in favour of betas being offered and required for artists for big things.

It's been particularly useful for me for big pieces that have been done over the span of weeks, when under a heavy deadline or when drawing inspiration from an external source. There's often last minute rushes and disconnection from all parts of influences. It distracts me and makes me miss out on very obvious mistakes, or only later realise I tried to put too much into a single frame. It can also plain burn me out and make me want to give up. Betas and cheerleaders are extremely reassuring. It's an external person looking at our work before we release it to a large public, someone to ask questions to, to hold hands with, to discuss and work out particular issues with our work. My works are much better when I can get a beta on it, and for challenges and exchanges I love to aim for the best quality of work I can make. Knowing betas are required pushes me to try newer things because I have a fail safe to look at the piece after and let me know if I'm off-track with it.