A google image on the term 'meat connective tissue' seems to show what I believe to be fat deposits/suet in the case of meat pictures. So what then is the difference between fat deposits and connective tissue?
Suet is a particular fat from around the kidney area of cattle, it is not intramuscular.
I just learned from the other poster that adipose is considered a type of connective tissue, so from that perspective they are the same thing. However, I when chefs say it the fat would be something flavorful that you can render easily, and connective tissue would be a tough fibrous structural component that takes much longer to break down with heat. You can certainly feel the difference when you touch it, despite it not looking all that different in a photograph.
Here is a man separating connective tissue from suet https://www.youtube.com/watch?v=ypRsO9KdxXk&t=190s
Fat is a type of connective tissue, alongside bone, tendons, cartilage.