so what CS is for in the real world?
Theoretical computer science can inform the use and design of practical tools that apply it, same as any other field. Theory is for asking questions and looking for answers. Application is for understanding real-world implications of the answers. Practice is for putting them to work.
The issue in the US education system is that we have one degree we call "computer science" which teaches all three of those pieces, each of which insists it's the real piece, and the students, faculty, administration, and employers all have very different expectations about what it means to have the degree.
Thing is, though, that of those who get CS degrees who stay in that kind of area, 90% are going to work as software engineers, not as theoretical computer scientists or computer engineers.
We really ought to split CS into three different departments: CS, software engineering, and computer engineering. The first one belongs in with the sciences, the last two belong in with the engineering fields. This would leave a much smaller CS department, though, so there's probably entrenched academic interests against this happening.
I use the analogy of chemistry: You have a chemistry department that thinks about the properties of atoms, and where the outer shell electrons go in molecules, and how the reactions occur. And then you have a chemical engineering department that thinks about how to make the stuff in multi-ton quantities without blowing up the city. They cover somewhat related material, but with completely different goals and mindsets.