That would never work, not to a degree that audiences would find satisfying. It takes human talent to create an effective performance. Even the most advanced "computer animation" is animated by humans using computers as their medium. And of course voice work is always done by real actors. Only the most arrogant director would think they were sufficiently skilled in every aspect of filmmaking that they could do it all themselves without collaborating with experts specializing in all the different aspects of film production. Of course, there are directors that arrogant, but their output without collaborators probably wouldn't be very good (as seen by comparing the Star Wars prequels, where George Lucas assumed he could write and direct them nearly all by himself, with the original trilogy, where he had the better sense to trust his collaborators more than his ego).
And after all, the Federation is a society where people don't have to work for basic subsistence and are free to work in pursuit of their dreams and fulfill their best potentials, right? Surely that includes people like actors, set designers, composers, etc. -- people who would want to do that work because they loved it. The talent would be there to draw on, so why not draw on it?
I mean, you might as well say that they could do all space exploration with robot probes. It'd certainly be safer. And yes, they could do that, but they don't, because letting computers do all their living for them is not how Federation citizens roll.
I'm often tempted to have a character in one of my books or stories make a pop-culture reference, only to realize it's unlikely that a character from that far in the future would be familiar with the thing I want to reference, so I have to leave it out.