I’ve noticed how animals tend to just roam in a very small area rather than across the map, regarded of whether they are fenced in or not. This isn’t a huge issue for 99% of the time as the animals will be in enclosures.
However we know that breakouts are planned, and it would be more challenging to have to deal with a tyrannosaur that’s more likely to roam across the entire map than just near where it broke out.
It would also be a great way to add diversity, to make some animals prefer a smaller range, and some animals naturally want to constantly move around.