SAS
Height - it is possible to end in a spiral or even a G stall and spin. Yes, I know unlikely, ham fisted agreed, but a new PPL might just do so, particularly on a type on which he was relatively new.
Airframe - what about practising a bit of slow flight before, possible to forget to put the flaps away. I have seen it done more than once.
Security - I agree not to much of a problem, but still a nuisance if the maps on the seat to your right end up on the floor.
Engine - always worth a quick check surely - it is a glance over the panel. I can think of at least one type where if you have a quarter of a tank or less of fuel you can end up with starvation issues.
Lookout - the most important. See the comment earlier on this thread by Rallye Driver.
Location - not a good idea to be doing steep turns in the same area to often. The fact is instructors and pilots will often do not one steep turn but put a few together one after the other.
Having read the posts I agree you can easily talk yourself out of a HASELL and might even be right to do so. Steep turns in proficient hands should not the slightest of issues and other than a good lookout, dispense with the rest. However it is 30 seconds out of your life, it is a good and quick nemonic, and it only needs to avoid a problem once to have proved its worth.
.. .. .. so why not?