Chess.com told Hikaru that he has to deal with random glitches which nobody else will face.
One of the reasons is that Hikaru can literally break chess.com
On chess.com Hikaru is followed by a million people.
So whenever he plays a game a million people get a notification of him playing.
Chess.com servers are capable of handling such a huge load.
Hence, they told Hikaru can play with an alternate account during the tournament to avoid any glitches.
How cool is that? Don't forget to share the news.