Pretty much any commercial activity now requires a defined system of risk assessment as part of a Safety Management System, set out in the operator's manuals. What format and how extensive is the same as the how long is a piece of string argument, but you need 'something'.
Does this make any difference to what people really do? Well, one way of looking at it is that it gives you more paperwork to fill in and more ways to be hung if something goes wrong, and is likely to get in the way of just clearing your head and focussing on the job at hand. Another way is that a simple, effective system might contribute a bit to making sure things don't get missed.
I'd say keep it as simple as possible, don't let the tail wag the dog, cut out anything resembling 2 hour mine site type safety induction time wasting but have something where you can put your hand on your heart and say we thought about the likely gotchas and what to do about them if they arose.
As to the particular reg that requires it, it's set out in 119, 138, 133, 135 etc as appropriate to the operation, basically saying you need an SMS and to have done risk assessments before various activities.