>>106982463
They are overall more spacious inside as they dont have to hold bays for older hard drives, usually they now with space for 1 brick hard drive or 2 SDD (or both) that end up hidden with the psu
They also dont need to have optic drive bays which means that the frontals can be used fully for air intake, they also have space for extra fans
Way easier build and tidier cable management as they now have more openings around the motherboard base

Its probably not the biggest deal but if you find the money to get a decent modern case is worth considering.
Picrel left is my old case (i wanted to use a real example), right is a case that i shill often in these threads because i found it to be damn good for its price