People are more likely to spend time on the app if it is fun and challenging and not just laborious. That's why having games works so well. I think however, the app is missing ways to review verses you've already learned in a fun and exciting way besides just "type out". What if there was a game involving a timer that counted down from say 20 seconds? The game would shuffle your verses and show you the reference for one. You would be responsible to type out the verse (same method as Type Out) before the timer reaches zero. If you succeed, another 10 seconds is added to the timer. For every error you make in typing you lose 1 second. The game continues until you have successfully completed all of your memory verses or until the timer reaches zero. The most important part is the score at the end. If the timer reached zero, your score would be displayed as a percentage value of the total of your verses you were able to complete. For instance, "You completed 68% of your verses before the timer reached zero". But if you complete 100% of your verses before the timer reaches zero, the amount of time left on the timer works as your score. If I was really fast and managed to get a bunch of time added to the timer by completing verses, the ending score would read "Congratulations! You completed 100% of your verses with 46 seconds left. Your highest score is 53 seconds" It's important to keep track of my scores and my high scores so that I desire to come back and practice over and over to beat the high score.
Other game idea would be called "Verbatim" and it's the same idea as above except without the timer. You receive a reference for a verse you have memorized. Type it out. Then receive another verse. You keep going until you make a single mistake. One mistake ends the game. Again the scoring at the end is key. Either "you completed 23% of your verses" or "you completed 100% of your verses in 4 minutes and 11 seconds." As long as my high score is recorded I'm coming back to beat it.