Hmmm some interesting points raised, thanks guys. I agree if it's a multi crew operation both pilot's must be rated on type and paid.
I was under the impression that a 'safety pilot' would refer to a 'helper' on a SPA flight... as usedtofly said - I see it as a way to just gain some additional operational experience outside my current scope of flying and... hopefully make some contacts and open possible doors later on down the line.