At Planty re 32Gigs.
I've got enough audio books to nearly fill a 256Gb SD card. I've got over 1.5Tb of music. I've got enough e.books to choke a server. There's no way in hell I can eviscerate all that media down to a mere 32Gb, especially not if that space also has to store apps, app data, OS updates, etc. Even the 128Gb model isn't enough, especially if you ever end up in areas of no cell coverage, no wifi coverage, & must therefor rely upon only what's in the phone at the time. "But there's ubiquitous coverage everywhere!" is such a load of shite you need to be bitch slapped. NO it is NOT ubiquitous. Maybe where YOU live but not in 90% of the rest of the world. Outside a freeway corridore, major metropolitan area (& sometimes not even there given dead zones), or outside the carrier's actual store, you can't count on being able to connect at all to "the cloud". No cloud means no streaming, no syncing, & no getting your media from anywhere not already on the phone. So what to do then? Will you be happy with what's on your phone *right now*? Because that's it, no signal means no more options.
Don't scoff at the desire for expandable storage. There are more reasons to want it than mere capacity in the phones. Once you're strapped into the bus/plane/train seat & see that you've got zero signal, THEN you'll understand the desire to be able to take "your digital life with you".