Agtrigormortis hit the bullseye. In survival mode you have players focusing largely on building, players focusing largely on surviving, and players in the middle. You want to cater towards all these groups, hence the peaceful - hard difficulty range.
When I play survival mode I prefer to focus on the survival, but that’s just me. As we’ve demonstrated there are others with different play styles and that’s great, those differences is what keeps the game going.
However, I do believe there is a valid argument to be had that over time the game has leaned increasingly towards building / collecting rather than survival. Which is fine, but I don’t think that play style should get all the attention. I originally imagined this suggestion as a way to provide some challenge for hard mode players, fear yet overall not much to normal mode players, and nothing to easy mode players, as I by no means wish to force my way of playing onto others. This way, the change can appeal to everyone.