Hi Sami.
It depends what you want out of charting I guess. From just charting cm you will know approximately when you O and will be able to time DTD. The advantages of charting your temp are that you will know exactly which day you ovulate (and therefore know your due date more accurately), you will know what day to expect AF, and what day to test. Although when charting your temp you can tend to get a bit obsessive and the stress might not be good, lol. But you're more likely to find out if anything's not quite right sooner, e.g. if you have a short luteal phase.
Good luck!