In the twenty-first century, animators use/are using computers to help them.

[diamondcutter]

In the twentieth century, movie makers began making animated movies by painting thousands of pictures onto sheets of clear plastic called cels, and then photographing them one by one onto motion picture film. ...
In the twenty-first century, animators use computers to help them. But even with the help of a computer, it still takes a long time and a lot of people to make an animated movie.

(Reading Tracks 2, International Language Teaching Services Ltd)

I wonder if it’s better to rewrite this sentence--In the twenty-first century, animators use computers to help them--as follows.

In the twenty-first century, animators are using computers to help them.

My reason is that it’s clear to see the beginning and ending points of time of the action: the twenty-first century.

 

[tedmc]

I think the simple present tense fits the sentence better as it is a plain statement of fact and is consistent with the sentence that follows.

 

[GoesStation]

The present simple is the right tense for the sentence. The continuous doesn't work.

It's not generally useful for learners to spend time looking for errors in native speakers' English. Such errors exist, but they're not common in formal publications. Your time would be better spent studying, reading, and listening.