They held one last year under the shadow of the Microsoft acquisition - granted, it wasn’t official yet, but friggin Phil Spencer showed up bc everyone knew it was going to go through - so I don’t think it’s explicitly Microsoft interfering. This feels more like the realization that, like last year, they don’t have that much exciting content to hype right now. They already milked their 3-part WoW xpac news dry, all they’ve got left is… Diablo season 4 or the seasonal new Overwatch character? Can’t build a convention around that.
Bottom line, there’s always a possibility a cloud/service provider could lose you data. That chance is (/should be) exponentially smaller on their environments however than the likelihood of your own local stores.
If you’re really serious about preserving your data, consider the 3-2-1 Backup Rule:
3 copies of your data 2 different types of media 1 copy stored off-site