I read a blog that the Black screen of death cause by Xbox One Insider can be fix by performing a factory reset - which unfortunately wipes all game data and saves from memory according to Xbox One's Black Screen of Death Glitch Returns For Insiders
I feel it is not a good idea to be an Xbox One Insider beta tester if you don't want to risk breaking your console, losing all your game data and game saves.
Yeah, there is no way I want to ever be an "insider" for anything, to be honest. Being able to try something new is not enough of a benefit when so many things can go wrong.
The Xbox One is an older console, so I feel there may not be many great Insider features left to add to the console, and there may not be huge increase in performance from Insider updates which are not worth the risk of losing all your game console's game data, game saves, and the risk of broken console which maybe difficult to fix for most average gamers.