As far as I can tell, the tap to reveal feature progressively shows what’s in between commas. If there’s a long section without commas, sometimes it can be a little counter-productive in that it wouldn’t be much different than reading it outright. Great app though! Super helpful!
I would like to be able to see only one word at a time revealed with touch. there are no other apps that I can find in the Apple Store that provide this feature in a USEABLE manner. But scrolling would also have to work because I memorise long passages at a time.