It does actually have a practical use.
Brahim Diaz reveals why he COPIED his Real Madrid team-mate Jude Bellingham by cutting holes in his socks
Oh, So That's Why Footballers Cut Holes In The Back Of Their Socks
Lot of soccer socks - Accessories
England and Arsenal star Bukayo Saka cuts holes in his socks - but why does he do this and who else does?
Anybody know why Dom has holes cutout in his socks? I didn't see any other player with this : r/Everton
Oh, So That's Why Footballers Cut Holes In The Back Of Their Socks
The reason why footballers cut holes in their socks
Richard Keys blasts Chelsea's Conor Gallagher for cutting huge holes in his socks against Man City as he calls for 'this nonsense to be outlawed' in social media rant
Boy Who Inspired Jack Grealish's World Cup Goal Dance Wants Footballer To Know This
Why are footballers cutting holes in their socks?