With all the time we spend on all of the other details on setting up a plane it just seems amiss to not balance the prop.

It's relatively quick and easy and it gives you a chance to putter around with the toys. If you do them all at the same time then it's a simple operation.
I balance new props before I hang them on my "reserve stock" wall and then I know that they are ready to go when I grab them.

As MinnFlyer said, It may not be as critical on smaller (composit/plastic) props, but on larger ones it really begins to show if a prop is out of balance. I like wood props and they can be WAY out of balance due to differences in wood density over the length of the prop. I've had 9" and 10" wood props so bad that they made the plane sound as if it had a doorbuzzer on it at mid RPMs on the bench. You could literally see the wave form/rippling on the wing covering from the vibration...that certainly had to be stressfull on the glue joints.

It's missing the small details sometimes that causes a failure that wrecks a plane. Getting into a habit of paying attention to detail, such as balancing, may be tedious, but it can save a lot of grief later. Good habits never hurt. Some folks can carry that to an extreme, but I don't think that balancing props is obsesive.