Shakman didn’t reveal why they opted to cut the moment, but while he didn’t elaborate on how that was going to look, it’s possible that it could be a reverse effect of how Wanda unintentionally created Vision in Westview. In the end, just like everyone else in her fantasy world, the synthezoid disintegrated as the hex came down. It was a gradual disappearance, but as the couple bid each other goodbye, there was a promise that somehow they’ll be reunited again. The WandaVision scene was quiet and somber, making it so much sadder and effective, so in hindsight, everything might have worked out for the best.
Given what’s known about the cut scene, it would’ve also further emphasized how powerful Scarlet Witch has become since the start of the show. As with the hex, she didn’t really understand how exactly she created the pocket reality in Westview. It was only when Agatha Harkness explained to her that it was Chaos Magic that she found out. And yet, the WandaVision finale almost showed her actively reversing what she created by binding Vision back to her.
Source: The Empire Film Podcast
Originally from https://screenrant.com/wandavision-show-scarlet-witch-vision-creator-alternate-ending/