Why does item level matter?

I understand it affects socket counts, is there any other reason?

For example, I have two gold rings:

10% Increased - Item level 17
13% Increased - Item level 10

Is there any difference here with regard to crafting these rings?

Items with higher Ilvl can get better mods

for example:
the lvl 10 ring may only get a mod with up to 30 life, while the lvl 17 may can get a life mod with up to 50 life(not the actuall numbers, u can look up the exact values somewhere)