Menial tasks (like sharing requests among the different tools, applying common encodings or navigating the GUI) should be as fast and transparent as possible, in order to free time and brain power for harder subjects.
Recurrent tasks (like brute-forcing a CSRF-protected form, frobbing an opaque blob of data, logging-in automatically or doing 1-byte fuzzing of a specific parameter) should be executed without having to think too much about it, thanks to prior rehearsals.
Advanced tasks (like managing a complex state, dealing with a custom format or testing authorizations) should be doable exclusively in Burp Suite Pro, possibly with the help of session handling rules or specific extensions.
All these tasks require testers to live-assess themselves, in order to detect as early as possible any error and to allow for correction and self-improvement.