A question of cadence

Hi everyone just going into my fourth offseason of tri from being completely sedentary.

Just started structured training for the first time and recently bought a power meter.

Never looked at cadence stats before but my natural cadence comes out to be about 80.

On the podcast it’s been suggested that 90s are better by Chad my question is why? Does it really matter? It seems harder to cycle at my watts at 90 than 80

I am no expert but I think higher cadence is recommended because it puts less strain on your legs and more strain on cardio.