4-elements Monk

[Asisreo1]

I know. Which was the whole point of including #3 in that list...

The ability to force multiple saves for the same ki cost means that despite targeting Con, you're likely to land more effects with Stunning Strike than, say, Clench of the North Wind.

CNW gives you paralysis, which is stronger than stun because you auto-crit when it lands, it forces the save without relying on hitting, it can target up to 4 humanoids in one turn, it's a wisdom save, and it's continuous for your concentration rather than just until your next turn.

I'm not saying CNW is Better than stun strike, but there's an argument that, depending on the fight, CNW might come in clutch rather than stunning strike. What you have said is true but it's worthwhile to make judgements about your toolkit but I think the differences are enough that they aren't a redundant feature. It gives options for paralysis/stunning.