Situation:

I have a content type with roughly 50k nodes and I have a view that displays some summarize data of the nodes. I decided I wanted to group the view items by a category that wasn't available or envisioned during the inception period of the data and site. I could go to my content type and add a new field, dump the data, fix it by using feeds tamper or something, and reimport it. OR, much simpler, use Rule Sets and Views Bulk Operations to get the job done.

Solution: