Well I’ll start this off i guess.
“What do I get out of learning this program called Blender3D?”
Well obviously modeling, but beyond that so much more.
First good models have proper topology and to do that there is some thinking required. Building complex topology is like a puzzle for the brain and a good challenge that develops new pathways inside of the brain (good for the brain). Modeling also opens you up to the intricate detail the objects you are making are made of. To model one need a whole lot of references and an extreme attention to detail. Researching your model will make you more knowledgeable on the background of the model as well as its construction.
Upon finishing modeling, texturing and materials are required. Textures require skills in art, as you are drawing with a digital pen called a stylus. As you are drawing you are improving the muscles in the hand, and again you have to critically think about how/what you are drawing to make something good.
Next up is lighting and composition. Knowledge of light and color theory is vital to creating good looking art, and once again it is not a matter of just placing random lights, but rather thinking about how each piece affects the whole.
Last step (really a loop) is getting critique. And not just getting critique but learning to to use it properly. Using that critique to improve your work.
“Why should I learn computer science?”
Every day I am surprised at how computer illiterate most people are. To give an example, there was a student in an aerospace engineering lecture that had no idea what a .rar file was or how to use it that the professor told us to download. Technology will only advance forward. We are living in a digital age after all! Learning about computers is not as hard as it may seem. The components inside a computer case should be known to anyone who is using a computer, yet unfortunately that is not the case. Knowing what is inside the computer case, and the basics of how those components function will make one aware of what their machine is capable of, what its weak spots are and of corse since things do break, at least an idea of what might be wrong. The user can even prevent hardware failures, through regular maintenance, and extend the life of the computer. On the software side, some of those things apply as well. Regular maintenance of the OS and the HDD will keep the system fast and snappy. Knowledge of more advanced programs and the command console will open more doors to the user, and make them more efficient. Even simple programming concepts may make daunting tasks easy with simple automated scrips. And for people going into fields where they might be expected to use computers, knowledge of CompSci will give them a leverage on others.
“What does learning this stuff get me in the real world?”,
"What can I do with it? "
No one will use all the things they learn in their lifetime, however that doesnt mean they shouldn’t. Studying a particular subject doesn’t always have a direct affect ona person, sometimes its the indirect effect that counts more. There is alot more going on behind the scenes of learning then only the subjects itself. Subjects like math and science help develop critical thinking and problem solving skills, while writing and art strengthen the creative side of the mind. The brain then uses all the skills it learns together after the learning is done.
As far as the specifics go, learning Blender, and CompSci, may land you a high paying job (esp CompSci)!
“How hard is this stuff to learn?”
Some things are harder to learn than others, and some people pick up on some thing faster than other, so there is no definite answer how a hypothetical High School student will pick up the knowledge offered. Also how far one is willing to learn is also a factor. The basics are always easy, its the advanced stuff that is always the challenge. Research is the key and another skill that comes off of any learning process. Fast and efficient research skill are obtained, they are not present at the start.
I am sure I have missed a lot of points, that perhaps others can fill in, but this is my opinions and views on the given subject.