Reasons
I would like to comment from the rampie side, boys and girls!
First there is three ways of depressurisation,
1: CB
2: PIN
3: DISCONNECT THE TORQUE LINK
As for gear locks this refers to a/c types such as MD83 or SAAB 340 /2000 Etc.
Remember safety is the importance and a/c differs with type?
Also different Airlines and aircraft specify different rules.
No HYD can cause a nose wheel to fail, these rules are written into ramp manuals for safety it will never happen?
SO WHY IS IT WRITTEN?