Packages get updated a lot in arch. Occasionally a package may push an update with a big that can cause major problems. Often times those bugs are fixed relatively quickly, but if you update too often, you are more likely to update to a package with such bugs.
The article didn’t really explain anything though. All it did was mention a couple types of processors that may benefit.
Someone more knowledgeable can correct me, but the main idea is that pinning can dedicate (or pin) certain cores to a specific process such as a game to improve performance.
Parking can dynamically disable cores not needed for the process, improving thermals and energy consumption.