It certainly isn’t but I’d argue the concept of “You play the hand you are given” as @Kerridoc has put it before only extends to a certain point.
The saying is true enough for a beginner to mid level player.
I’ll ascend enough 5* to do the daily grind eg farm rare quests and events and that’s it.
There’s no utility in ascending others.
Of course… That drum has been beaten for some time now but surely it is common knowledge that some defences are harder to beat than others eg those that have Kunchen, Black Knight and Guin.
The “any defence can be beaten” motto equates to classic hero holders relying on luck more than anything else to break through.
Because the gap is too large and luck is all we have.
Of course there is strategy for sure for those lacking the heavy hitters but having better heroes reduces the luck required to beat those superstar teams.
When you face a sea of Kunchens in war there is little utility in ascending some of the classic heroes pulled.
You need the Ariels and Grazuls to stand a better chance