As my knowledge, you cannot use app while it is hidden, you have to unhide that app to use thatAnother option is to open the hidden app, search it in playstore and open it from there
I haven't exchanged my deviceBut i have checked itLike my smartphone has 3k exchange value and exchange bonus is 17kSo they give me discount of 20kI have checked this for s24+They offered me s24+ for 80k after 20k discount