You are asking if this activity is “worth it” for top 50 colleges. I am going to give you the answer that you specifically said you do not want to hear, but it is the truth.
This is a perfectly good, valuable summer activity for a HS student. If you enjoy it, then do it!
And…you said that you like teaching and talking about what you love. This is great! I have no doubt that your students will pick up on your enthusiasm and will tell their families how much they love the program.