I think it's devolved into mostly getting in the way and generating perverse outcomes.

Used to be if you skipped town the local authorities would have no way of tracking you down. And authorities where ever you fled to would often have no ability to tell if you had a warrant. That's mostly not true anymore.

So then you have people sitting in jail because they're broke, probably too broke to fee even. And for crimes where if they did flee might be in everyone's interest. The police will surely be heartbroken to find out a local trouble maker decided to leave town. /s