And the fact that Jaylen is shooting as well or better than Tatum could be taken in two ways. I see most taking it as Jaylen improving. And he may well have. But just as likely, this should temper what this sort of practice really means (which is not much).
The other day my 13 year old made 15 threes in a row and frequently hits over 90% of threes in practice. So basically, it's cool but nothing spectacular.