When working with wood that you intend to sit on or handle in any way it is useful to be able to smooth it. Smooth wood minimizes splinters and makes it feel softer to the touch. There are a variety of ways to do so. A good scraper can go a long way towards smooth and soft to the touch wood. A pocket knife can do similar work but it is hard on the blade. A scraper is preferable.
A scraper is really nothing more than a piece of steel wedged between two pieces of wood. I have seen some with two pieces of wood loosely riveted together. A simple wedge holds the steel in place. Others, like mine, are simply glued into place. The wedged variety works better as it allows one to remove or change the position of the blade.
Dry goods stores have begun to offer scrapers with larger handles that work well. I prefer a card scraper as they are smaller and more comfortable for me to use. Honestly, until recently I could not have told you what a scraper was used for. Often at a stop on campaign I would take a hatchet and brace or bow drill to make a three legged stool or three. When wearing good britches a man need not really worry about a sliver in the tail end. When trying to make a nicer replacement chair for the delicate backside of a lady a smooth sliver free seating arrangement is advisable.
After review that smooth seat was a requirement. So I tried to smooth it to the ladies approval with a plane. That did not pass muster and I proceeded on to use the scraper. In short order my Mrs. Mina was happy with the result.
I have since taken to using a scraper on most of my creations. It works well.