The question you have asked has a clearly "yes" answer, but the devil's detail is that you bending the narratine (I would prefer to say that you are lying) about what are you doing in reality. You are addicting your peers to a (the) closed-source software which is running on the incredible unsafe device such as something with Android or something from Apple's walled garden.
When you are trying to make your student "streak of learning" what happens in reality is gluing the student to the device which effectively is a someone's social network client and nothing more. He/she is going to be bombarded with all kinds of dark patterns which are the essence of every snoop-phone. So, no matter how good teacher you are, I will never consider using a snoop-phone for a kid less than 18 years old as something ethical.
What is really ethical is to be an offline mentor/teacher for those who urge to study what you have already mastered. Tomas Edison once has said that the video industry is going to be the best creation of all times to enhance learning. I understand why he used to think like that. But from my experience of working with teenagers, learning is just not possible when there is something other than plain text has involved.
Learning is not when the app shows some sad picture and the learner starts doing anything in order to make sad picture happy. Learning (if not under academia which goals is not 100% of making students smarter) is making your student to yield some really smart questions. Learning is hunting in my pov, learning (no matter what industry) is always about reverse engineering, learning is continuously sitting calmly and solving some tasks interesting to learner, not being bombarded with notifications profitable for Alphabet or Apple or you.