I usually use the cutting blade to cut out vinyls so that its easy to remove and apply. I was wondering can I use the same blade to cut poster paper and save us the hassle of cutting the posters?
You can cut paper with a plotter but not for very long without ruining the blade. The blade on a vinyl cutter cuts with just the tip and paper is extremely abrasive. Cutting paper will wear the tip off the blade in short order.
Moreover, there is no backing on poster paper so you'll be whittling away at your cutting strip. Some plotters have a perf cut option but you're still cutting paper with a blade intended to cut vinyl.
This is one of those things that you can do but you probably shouldn't.