Review the words, but not straight away
A word just learnt is soon forgotten unless it is reviewed at the right time. Independent mode keeps the words to work on again.
A word just learnt is soon forgotten, but each review slows down the next forgetting. Independent mode keeps each pupil's words to work on again, to review them a few days later.
The Eduscol guide on teaching vocabulary in preschool (2020) says so: “Repeated learning at regular intervals improves memorisation” (page 30, translated from French). Self-testing also works better than rereading, as Stanislas Dehaene shows in Apprendre ! (2018).
A bingo on Monday, a memory game on Wednesday and a worksheet on Friday work better than an hour of vocabulary in a row. Old resources stay ready to be played again.