A drill paddle mixer is built for tackling small jobs such as mixing paint and grout. While it is also good for mixing cement, filler and plaster, it's the power of the drill and the size of the drill paddle mixer that limits what jobs you can tackle.
If you only need to mix small amounts of cement or plaster you are good to go. But, if you want to mix large quantities of cement or plaster you will need a more powerful tool such as this DEWALT Dual Handle Paddle Mixer from Amazon