Isn't the main reason to use experienced, reliable actors that there is a budget and schedule to make and you need people who can reliably deliver? 2nd reason

Isn't the main reason to use experienced, reliable actors that there is a budget and schedule to make and you need people who can reliably deliver? 2nd reason being to use their names to promote the movie? For reliability, it will be hard to beat AIs: they don't die or get hangovers and you can dial their age and mood back and forth.