I think it's a combination of three factors: 1. Historically, before it was taught in Java, this unit was taught in C, and it would have been a natural transit

I think it's a combination of three factors: 1. Historically, before it was taught in Java, this unit was taught in C, and it would have been a natural transition from building data structures via explicit pointer manipulation to explaining stack frames as a specialised data structure for handling scoped variables in function calls. 2. Despite the move to a higher level language (and, from assembly and machine code, even C is a higher level language), it's good for the students to get some exposure to the machine model, and what is going on deeper in the stack of turtles. 3. The lecturer who runs the course also has a bit of the Yorkshirewoman in her. So students learn a tiny bit of MIPS like they should eat their spinach and shower with cold water, uphill both ways, in the snow, or something.