I haven’t watched many of Melanie’s videos (and even then, it was a while ago), so I’m not sure which one you’re referring to. But I think MC hand-offs, just like IC ones, can work (within a single storyform), as long as they share the same MC Throughline storypoints. The only issue is that it may be challenging to pull off and that it might confuse the audience (hence why it’s usually rare): otherwise, it’s possible. Here’s a thread that explains it further:
Most of the time, having multiple MCs or MC hand-offs is the result of having multiple stories within one work (Psycho is the first to come to mind).