Why do I have different options for the same feature? The Glance Screen dilemma?

[nci88]

Hi everyone! I have a Lumia 830 and a 930, but I've tried also the 640 and 640xl.
I've noticed that there's different options for the Glance Screen and so far I know that:

Cool G.S.: the 830 has the possibility to set a picture in the glance screen and it can display also the date

Notsocool G.S.: the 640/XL just shows the black screen, the time and notifications

The question is: how about the other phones?

 

[libra89]

I think Glance is varied because of hardware limitations. Not really sure if there's any other reason.