Use of de-aging software

There is a movie coming out soon Featuring Tom hanks. For a good portion of it he will be de-aged. I have seen de-aging used in The Irishman, and in Sullivan's Crossing.

In The Irishman, the failure is the stilted movement from the actors. This movement clearly betrays their age. More than any wrinkles ever could. With Sullivan's Crossing the issue is that I know what the actor really looked like at that age. 

In either case, it fails abysmally. So why does it keep getting used? One answer might be that on balance it is cheaper to use one actor and run them through a wrinkle smoothing algorithm than to pay two or more actors to play the role.

Is it really cheaper though if people notice the lack of quality and it reduces their interest in your project? With The Irishman I have zero desire to ever rewatch it. With Sullivan's Crossing I won't know if I would rewatch it until the series is over.

Royalty payments sustain most actors between projects. It stands to reason that this software may be undercutting young talent in favor of making more money for the studio. Many times I was first introduced to a favorite actor because they played a younger version of someone well known. Personally, I would far rather see young talent on the screen.