Welcome to Jurassic Art
At least for the time being, art is the primary way we experience dinosaurs. We can study bones and fossils, but barring the invention of time travel, we will never see how these animals lived with our own eyes. There are no photos or videos, of course, which means that if we want to picture how they look, someone has to draw them.
The illustrated interpretation of dinosaur morphology and behavior has had a big impact on how the public views dinosaurs and it's gone through a couple of key turning points, including a more recent push for more speculative paleoart.