Just more of a good sign that Jaylen Brown is going to continue to be a mentally tough, hard worker. Not that I questioned it at all based on what we already know of him. But this shows that it's a trend in his family which probably means it's ingrained in him.
On the growth thing, that would be cool if he added an inch or two in height. Not necessary because he is already decent size, but it could help set him apart.
Guys who I believe grew after being in the league:
Paul George
Giannis
Durant
I remember reading about some Euro drafted during the last lockout year who had grown signigicantly (reported like 3 inches or something) by the time the season started. Can't remember who or if he even ended up in the league.