Messi is as half of the strategy, and Alves is as important as with him in attack..and he really seems to control his life, so that he can play in peak as long as much unlike former brazilian players. Thanks to his new love maybe
That's actually a great idea in my opinion.
Dani has been at the club for 7 years and he is very important in the dressing room. If it gives him motivation (as he said in his post on Instagram), then it's perfect.
When Dani Alves had number 20: We won Champions League
When Dani Alves had number 2: We won Champions League
When Dani Alves had number 22: We won Champions League
Now it remains to see if he can do it with the number 6 on his back.