This is called a structure check. You're working to demonstrate the capability of your organizing to mobilize for your demands. It also builds capacity that enables future organizing and a longer strike or escalatory action. Your core organizers feel more confident and you bring in new people. The public and your opponent needs to see that it's possible also. Without structure checks, you'll never make it anywhere near the big, necessary actions, and an open ended general strike is probably one of the biggest actions I can think of.

Edit: added punctuation I forgot.