I’m aware of the psychological aspect to it, which is why it’s presented as a difficulty scale rating “survivability” rather than describing how “powerful” the character is. Of COURSE people are going to play as “demigod”, there’s no down side. But if that’s explicitly stated as an “easy character”, I think a lot of people will take up the challenge of playing more limited and difficult characters.
In df the distinction between a normal and demigod character was also pointless, you could trivially grind to make up the difference, so starting out as a demigod was simply skipping the early game grind.
In DDA, there are some transient stats you can make up in game, but 1. surviving early game in cata is a lot harder than df (last I played anyway) 2. we do have a lot of permanent traits you can only take at game start.