Because it was drizzling and my boots were slippery, I did not continue to venture upwards and went back down. It's amazing that you can see waterfalls within 15min from the train station. If you want to venture more upwards, the trail becomes more difficult without handles so you should ideally do it with proper hiking shoes, equipment and during a fine weather. But if you don't want to walk at all, there is always a ropeway up the mountain to visit the Nunobiki Herb Garden.
Official Website: http://www.feel-kobe.jp/_en/sightseeing/spot/?sid=153