What is electronic line calling and why has it been controversial?

What is electronic line calling at Wimbledon and why has it been controversial? - Wimbledon will also introduce the use of ...
The New York Times

Tennis adopted electronic line calling on clay and created a ball-mark monster

Aryna Sabalenka and other tennis stars are still getting used to electronic line calling on clay. Will Tullos / The Athletic; Getty Images “Can you make it make sense?” Alex Eala asked after her ...