I've long-called this USeless 641 because it doesn't touch its parent, is less than 300 miles long, and is not really a major route.
To combine the US 641 and I-69 subjects, I have never disagreed with the decision to route I-69 in Kentucky along the WK and Pennyrile parkways. The most direct route from Paducah to Henderson is US 60, not I-24 and the parkways. There have been a few upgrades to US 60 in the western part of the state, and completion of this improved US 641 would probably mean the shortest way to get to Evansville/Henderson from Paducah would be to take this new US 641 up to US 60 and then US 60 northeast. I haven't run a mileage comparison, but I'd think the all-parkway routing would be significantly longer.
It reminds me of the "new terrain vs. US 41/I-70" debate in Indiana.
Edited to fix a typo.