why we didn't see baryonyx or other dino that are on the site?

Well, not to sound mean, but:

...Because it was not in the movie.

Why was it not in the movie? Well maybe they didn't think of it, or maybe they just wanted to focus on other dinosaurs instead, maybe they're saving those dinosaurs for the upcoming sequels, the point I don't think there is a definite answer for that.

I hope they appear in the sequel

Yeah, I honestly was hoping for Baryonyx but the movie was great, so I won't complain.

There was probably no planned seens and those dinos could have been added to the site after, but then again you see a Baryonyx on a shirt, simple they had no seens to use them. I was hoping though.

Like Alan401 said, "it was not in the movie."

Baryonyx does show up as a playable Lego jurassic World dinosaur. Plus, if you look on the website...there's no animation design for them. They were brightly colored and just digital arts of them. While you look at T-rex, I-rex, etc. They were created by cgi.

They were just there on the website to just be there. For the hype most likely... 

Perhaps we will just ahve to wait for the next sequel to come out so we can see if they will have the Baronyx.