I guess the screen will be more likely to shatter and / or drop out.
The cracking will likely get worse over time and may eventually make the screen hard to read and / or parts of the screen may stop responding to touch.
If the cracks go all the way through, the device may be more prone to moisture damage which, in turn, could mean that when you finally decide to get it fixed, the supplier may refuse to touch it.
Otherwise, I see lots of people using devices with screens that look like crazy paving and they seem fine with it.