A similar thing has been happening in online contract bridge.
https://bridgewinners.com/article/view/the-2020-online-cheat...
https://bridgewinners.com/article/view/confession-of-a-self-...
https://bridgewinners.com/article/view/the-2020-online-cheat...
https://bridgewinners.com/article/view/confession-of-a-self-...
Still, being able to self-kibitz opens an extra avenue of cheating compared to collusion: you can cheat even if your partner is honest.
The downside is that people can kibitz their own table (if kibitzing is allowed) using an alt account. Yes, it's a risk, but there are lots of ways to cheat online. It's trivial to cheat using out of band communication with your partner, as a sibling comment points out, or use a computer program to calculate odds if cheating without the knowledge of your partner.
So the whole thing is built on an honor system.