It seems more that we now have a snapshot of Rembrant as he was when he died. Assuming that the man were immortal somehow, his style would continue to progress, each painting building upon the last. If this algorithm were to do that, it'd just be deviating from what we now consider a Rembrant. I don't think we'd appreciate when an algorithm spitting out pictures akin to Picassos Rose Period suddenly decided that Cubism was more his thing.

The computer didn't learn how to paint or even compose or even choose subjects like Rembrandt did. With the help of a team of experts, it assembled premade parts of Rembrandt's earlier paintings into a fancy collage under tight constraints. The heightmap algorithm was probably more interesting than the one that made the picture.