Continuity mistake: When Owen wraps the rope around the tree stump, the position of the rope changes between shots. Note the gap between the ropes. (00:08:30)
Deliberate mistake: The decaying tree trunk would have more than likely broken into pieces and/or uprooted from the force exerted by the rope tethered to the pulling Parasaurolophus when Owen wrapped the rope around the trunk to stop the heavy-weight dino, but the trunk held up without even losing a shred of bark. (00:08:36)
Continuity mistake: Blue's baby was standing along her left side when Owen told Maisie to breathe. After a quick camera shift, the baby dinosaur was further back, standing on a log that was more perpendicular to Blue. There had not been any sound suggesting that the baby dinosaur had moved, but there were footstep sounds after the baby jumped off the log. (00:27:47)
Continuity mistake: When Owen latches on the parasaurolophus he stops it with a tree trunk. He loses grip on his rope, leaving just a small bit of rope. He then ties a longer piece around the trunk. (00:08:44)
Revealing mistake: When Owen rides his bike on the runway towards the plane, his stunt double is very noticeable because he doesn't resemble him at all.
Character mistake: Towards the end of the movie when the Giganotosaurus is attacking the group and Claire gets the rope wrapped around her leg and pulled towards the dinosaur Owen actually shouts Bryce before saving her instead of Claire.
Revealing mistake: After Owen gets a lasso around the neck of the Parasaurolophus and is pulling on the rope, the noose loosens when it should remain taut. Also, the knot was in the center-front of the dino's neck and should have stayed there, but it somehow moved a couple inches clockwise. As Owen continued holding the rope tightly, the knot should have moved back to center-front or be too tight for the dinosaur to breathe. Next, based on the angle of the rope, the knot would be near the top of the neck. (00:08:41 - 00:09:30)
Continuity mistake: Maisie set the front tire of her bike against the side railing of the steps to the cabin. It looked like it might have been sliding down when the camera shifted. Even if the bike did slide onto its side, it was at a different angle on the ground and too far away from where it had been propped. A little later when Owen and Claire where about to go up the stairs, the bike's rear tire was along the front of the steps, not side. (00:12:28 - 00:14:32)
Answer: The live dinosaurs are genetically tweaked recreations, they're not the "pure" dinosaurs of the past, which would still be of great interest. Plus just like any other archaeology or historical study, there's always more to be learned about the past, and a great many people are interested in what the past has to teach us.