The Baiyang Waterfall has a nice swimming hole just behind the shack you see on the image. It’s not allowed but who cares?
They really splashed out on that article. All the photos are Wiki commons.
Also you can’t really see the Shifen waterfall on the Sandiaoling waterfall trail (which is a great hike btw). You’ll walk past the whole scenic area only if you finish the hike in Shifen and by walking on the railway. But you’d have to pay an entrance fee and backtrack to actually see it.
Comparing it to Niagara is ridiculous.