1080p Displays On Phones : Do you consider it as advantage ?

Its a general question.I have an iPad 3rd gen and Lumia 820

I always prefer to watch video content on my TV or Laptop.

Having good ppi (above 250 ppi) and decent screen size (4.3-4.7 maybe ?) is good enough for reading text on websites and for apps (personal opinion)

720p Looked good even on Note 2 screen size.

Is 1080p just a gimmick or do you really find some use in it ?

Just asking because if OEMs put same battery in a 720p screen instead of 1080p display , Battery life will be much better.

I rather opt for OEMs to keep 720p displays on smaller screens like 4.7 instead of going into 5 inch and improve other aspects of display instead of resolution.

Or Am I wrong And 1080p really is useful in real life usage ?