If you use your phone as a kindle more than as a phone, a large screen is better.
If you use your phone to read & send email more than as a phone, a large screen is better.
If you use your phone to catch up on Social Media while on the bus, a large screen is better.
If you use your phone a lot and desire a huge battery, a large screen allows for more real space.
If you use your phone as a phone but don't want to always put your glasses on first, a large screen is better.
Only the first affects me, but there are many reasons that people desire large phones with large screens.