People can lie, people can send emails that look like they're from your boss. People now know deepfakes are a thing and have an immunity from trusting suspicious online meetings where your boss acts different than they usually do. Etc etc. It's not as big of a threat as people want to make it out to be
People routinely fall for lies and get phished from those emails that look like they're from your boss. Every year there are a handful of high profile tech companies that get hacked because someone you would think should know better falls for a phishing scam. I think this is a bigger threat than people are making it out to be.
People get their company accounts compromised all the time.
It's one thing to get a poorly-worded email from your CFO asking for company bank info, but it's a whole other thing to be asked over a Zoom video call by who you think is the right person, but it's a fake gaussian splat avatar.
There's already precedent for scammers doing similar things using voice deepfaking over phone calls. This could be a whole new level of phishing.
Online meetings for important things are now unsecure because you can't be sure the other people are who they claim to be.