Depends on the saddlebag, those ones that clip to the saddle would be fine but with ones that tie round the post as well that’ll get in the way of the drop.
(oh, my Next’s been up and down like a yoyo, it’s probably about half as thick as it used to be but kit is for using not looking at so I don’t mind. A good quality alu post doesn’t have to be so much heavier though.)
I dunno, personally I think the benefits are way more than the drawbacks, except for the price, they are damn expensive. I think worth it but then I’m a disaster with money.
Also it might sound daft but mine really saved my legs in France, some of those rides were right on the limit of my fitness so being able to drop the post for short sections then fire it back up for pedals was a big deal, compared to dropping the post for long undulating sections.