When you get one you’ll find you use it loads. Sections of trail like Afan’s skyline descent, has lots of up / along bits in it where you want to pedal with saddle at the right height, then some techy bits like the rock steps where you really don’t want your saddle at full height and in the way. I find I use it a lot.
And if you are worried about weight – buy 2 posts and swap between them depending on the riding you are doing. That’s what I did for my anthem.
Trail centre = reverb, race = ibeam