NeuroLister gives you a range of item attributes that can be automatically added to your seller SKU. In your settings, you'll see options to add:
item cost
sales rank
inventory source
date
condition
weight
item price
inventory source
ASIN
Prefix of your choosing
Check the box for any attributes you'd like included in your SKU, and NeuroLister will take care of the rest (40 character limit).
Why is this useful?
Two reasons:
#1: Repricing.
Your repricer (hopefully NeuroPrice) should allow you to set custom rules based on SKU. You can set different pricing rules based on item cost, weight, etc (at least if you're using NeuroPrice).
#2: General tracking.
Tools like InventoryLab let you track metrics by SKU. Being able to filter by certain SKUs or SKU ranges allows you to track certain inventory more precisely.
Want to go deeper?
Here's an article on Peter Valley's site that covers this in-depth: