Bigger screens please PPIs can wait
See, it all started way back when Apple introduced the iPhone 4 with its 'Retina Display', meaning it had a screen with a pixel density of over 300 pixels per square inch of its surface. While it was and is still an impressive display, the pixel density of the screen wasn't necessarily the only thing making it as good as it was.
While Apple may have patented the term Retina Display and vigorously marketed it, and successfully; it relied on the IPS LCD panels produced by LG (mostly) to get those viewing angles, contrast and sunlight legibility.
Now Android top dogs these days seem to be pouring out 1080p displays that have pixel densities crossing 400 PPI. Even our very own Walton has done it! Overkill? Hell Yeah.
Adding so many pixels improves the image clarity and sharpness but the cost it has to pay is perhaps in need of a revision. Increasing the resolution means it need more power to push those pixels. This means your processor and GPU needs more power to show the same image in a higher resolution screen. As a result, your battery also has to eke out more juice, leading to a shorter battery-life.
In general, people are not concerned about pixel densities but rather, they are more aware with the term, Retina display. Yes, indisputably pixel density of a screen is important, especially when reading text, but it is not the biggest factor determining its quality. It's time manufacturers took notice and stopped with the pixel density overkill.