As stated in the starter guide, there is no practical difference. They both represent the same concept: life force and how it is manipulated. However, if you speak using the word "magic" as opposed to "energy", you will get a much different reaction from others in your OP group.
Why is this? In short, energy academia is the worst.
Magic is considered to be a childish archaic term used by old mystics who have no idea what they're speaking about. Operatives rarely feel the need to dig deep into the history of magical practices, or to look past what they are instructed to do with energy. Magic and energy might represent the same thing, but in practice, they are separate in categorical speech. If you ask an average OP, energy has a science behind it, a basis in facts and a tangible reality, while magic is frivolous and the product of uneducated dullards of times past.
Magic is spoken about with sneering dismissal.
Textbooks on energy and energy practice provided to operatives preach how there is an exact science and understanding to energy, but all answers they provide are shallow at best. The common explanations often miss the core concepts of magic, which is that magic cannot be fully understood or justified, because it is part of the unknowable.
Scientists and researchers hired by Leundafel are often baffled by energy, and struggle to make sense of it. General academia in Leundafel generally exists to uphold the status quo, not to change minds or discover any hidden truths. If their research doesn't benefit Leundafel's bottom line, it's considered useless. They are not driven by curiosity. Some go mad by the lack of conclusive understanding, as it flies in the face of how they perceive reality. Another downside of energy academia is how often morals are put aside for the sake of (often meaningless) research. The history of magic is kept under lock by the Leundafelan governing eye. Leundafel yearns to control everything—even the fabric of reality—in ways it never can. That will not stop them from trying.
One way energy academia affects practices is the concept of special abilities, expanded upon here: Special Abilities and Beyond