Great point Merdaneth, since you said "in most cases" could you elaborate a bit on the odd cases where it does mean something, in your opinion?
There are a few instances that people got their standings raised for specific (in-space) act of support of some cause or faction (like helping defend the Imperial Apocalypse I believe). Recently we had an incident where Sansha supporters got their standings lowered after aiding a Sansha attack while a CCP actor was in space.
Today CCP is able to use medals, which are a far nicer and more RP friendly tool to indicate that you've contributed to some cause, if you ask me.
If the Republic hands Miz a medal as a 'staunch defender of the Republic' for specific in-game action, then that's worth something to me IC. I wouldn't even look twice at her standings to determine loyalty, although it would indicate to me what mission she has run. And I can always ask about that.
Standings do give information, and they can be used in RP for sure. They just provide very little *loyalty* information and using them as a yardstick for loyalty is not my thing.