Ohysical? Is that the opposite of Pwn? ;-P
I think the 24-hour latency is an attunement phase, there to prevent you from handing the belts around.
The "24-hours as a temporary bonus" language is included primarily for the mental stat bonus items. It is intended to limit the wearing of such items to get bonus spells when you prepare/meditate in the morning, casting the bonus ones, and then removing the item (possibly passing it off to someone else).
There could also be a class with similar powers based on physical stats (see 3.0 Psion for instance), thus the identical language included. Also perhaps for things such as qualifying for feats (Power Attack, min Str 13).