Disney did this to ensure they get the rights to Mark Hamill’s likeness/voice.
They had to get agreements with the estates of Peter Cushing to use his likeness.
IIRC, they had to do something similar with Carrie Fisher about de-aging digital likeness for Rogue One.
More and more studios will start doing this.
Also, several actors have already stated no one is allowed to use their likeness after their death.