Mysteries has two personalities, and which one you meet depends entirely on the size of the swell.
When it is big
Large northwest swells make it one of the most technical take-offs in the area — the water sucks off the mixed reef and sand bottom and the drop becomes genuinely demanding. The shoulder that follows is more forgiving than the entry suggests, and it holds well in easterly offshores, allowing some of the widest turns going.
At that size there is a clearing take-off zone that drags surfers back towards the cliffs and beach, which is the main hazard here.
When it is small
A short, fun right that less-experienced intermediates can enjoy. It still asks you to travel down the line rather than ride straight, but the punishing take-off zone is absent.
That is why it is rated intermediate rather than advanced: the same spot is two different waves, and the forecast tells you which one you are getting.
Why it stays quieter
It sits between two famous names and most visitors walk past towards the breaks they recognise. On a moderate day that works in your favour.
Reading it first
Spend ten minutes watching from shore before deciding. Count the sets, see where people take off, check how the inside behaves. If you cannot identify a clean exit, that is your answer.