Why is level 1 'the worst'?

A level 1 character who plays it smart isn't going to have trouble surviving, even against higher level challenges.

It depends what you want out of the game I suppose. I prefer an experience that takes skill, that involves tension, pacing, where decisions matter, where mistakes are real but so are rewards, where if you earn something in game you actually feel you earned it. Hence my level 1 rule. It forces smart play and it means death matters.

If you want a power fantasy where death is meaningless and characters are super overpowered then sure that's your prerogative but I really don't enjoy those style of games as they just have no tension for me and ultimately my choices are meaningless as there's no consequences for my actions. I also find such power fantasy campaigns rarely have any legs on them as the characters are so covered in plot armour that it soon becomes obvious to the players that what they're doing doesn't matter. Although some players certainly just wanna turn up and so the TRPG equivalent of button mashing whilst following the games waypoint. Each to their own.

This article does a good job of going deeper into my point.

http://tao-dnd.blogspot.com/2019/03/starting-with-nothing.html?m=1