Cresswell has sealed a loan move to Millwall, who finished the 2021/22 season in ninth place, only six points behind Luton Town who took the last playoff place.
The 19-year-old was handed his Premier League debut against West Ham at Elland Road by Marcelo Bielsa amid a defensive crisis.
Cooper is of the opinion, based on his own loan experiences, that the England Under-21 international will come back from the loan spell with an entirely different mindset and also valuable experience that will serve him well.
“Charlie is an unbelievable player and it will only benefit him, going away and playing men’s football and being seen as one of the starters every week”, Cooper told the Yorkshire Evening Post.
“It’s a totally different mindset. How you prepare each game, how you stay fit.”
Cooper also pointed to the hectic schedule that is part and parcel of playing in the Championship, highlighting the experience as one that will only benefit the youngster and his parent club.
“In the Championship, it’s games every two or three days”, he added.
“It’s about keeping yourself mentally in there and getting yourself up for every single game and it’ll only benefit him and in the long run it will only benefit us as a club.”
Cresswell made five appearances in the Premier League last season, receiving just the one booking in an away win against Wolverhampton Wanderers.
Leeds managed to secure Premier League football for next season courtesy of a late Jack Harrison winner away to Brentford.