For some static hold exercises like handstand, lever or planche progressions it can be useful to have a toal hold time goal and try to achieve that in as few attempts as possible. For example you want to hold a 30s handstand in max 2 attempts. This method of training can be useful if you want to increase your hold times and not always go for your 1RM. As of now you would have to keep track in the notes or create new exercises named "exercises 20 seconds". But in the second approach the app always tries to increase the number of reps, which is ultimately not the goal of this method.