Mainly for

• chilling in bed or something, where a laptop is too clumsy
• digital art/drawing/notes (for me, may not apply to others)

We also have like 10-12" tablets now and I'm a small phone fan, so I could see like a 5.5" phone and 11" tablet working well.

What about a laptop or tablet? I usually only use my phone when I'm on the go or in a difficult situation.