This feels like an attempt to make YouTube more social media like, probably in response to TikTok and other platforms.

I have no desire of another "social" platform. I use YouTube to consume quick content, like looking up how to clean my espresso machine, how to do some manual labour or how to improve my serve in tennis. This is maybe a great feature for YouTubers but I don't think that is enough people to draw a critical mass to make this a useful feature. Most people probably don't even have an account or log into YouTube to consume content, let alone are interested in new social media features like a handle.

For those not logged in to YouTube: https://support.google.com/youtube/answer/11585688