Is it just that inkjet DL discs can be printed on on the outside or is the quality of whats on the disc better?

Is it just that inkjet DL discs can be printed on on the outside, or is it that the actual quality of what is on the disk is better? I am not sure it Inkjet printable just means that it can be printed on the outside, or if it us the quality of the items on the disc that are better.