Useless ? Certainly not.
Very limited space for a smartphone that also doubles as a phablet ? Definitely yes.
Considering that:
- the iOS itself leaves you only with ~11gb free
- average apps size have increased significantly
- Major upgrades of the iOS require around 4-5gb free on the device
...with a 16gb version many people will have issues.
Speaking of which, why did Apple stopped offering the 32gb version ?
Agree that 16 GB isn't useless in general, but even on the 6 Plus, it depends on the user and the extent to which they want to store media on their phone. If anything, the increased usage of streaming music and cloud storage has negated some of the need for local capacity.
I bought a 32 GB 5s last year because I assumed that I would store music on my phone. But, with iTunes Match, I only store music on my phone when I'm about to go on a road trip through some spotty coverage areas. I currently use 19.5 GB. However, I can also see myself purging many of the apps that I keep on my phone -- a lot of "app of the week" stuff and other freebies that I downloaded, but hardly ever use. Because I still have a lot of extra storage, I don't think much about which apps I actually use and which ones I should delete. If I was limited to 16 GB, of course I would think more about what I should keep on my phone.
Generally, app sizes have increased. However, the biggest size increases have been with games. For people who don't do a lot of gaming, most apps in other categories are still a lot smaller.
That 4-5 GB requirement only applies if you update iOS over-the-air. Plug the phone into a computer and update using iTunes, and the free space needed is reduced by more than half.
As to why Apple stopped offering the 32 GB configuration -- because people never stopped buying the 16 GB models. They see the sales distributions that we don't, so they made a calculation based on what they know about their customers. For the same price as the 32 GB iPhone 5s last year, you can now buy a 64 GB iPhone 6. Apple chose the incentive to prod consumers to opt for the higher priced configuration, rather than essentially dropping the price on the entry level configuration.
