I don't like that at all as it changes too much tactically. Kounde has actually been good in offense as RB, we'd lose that with Araujo. Kounde is also good under pressure at RB and much better on the ball at RB compared to CB.I have a feeling Xavi will put Araujo on the left again as he does against Vinicius. I also think Araujo is way better in 1on1s and I trust him more to stop Mbappe.
Besides, Mbappe will move in central just like Vini did. Araujo will have his hands full at RCB as well.