I can see an argument for High-Viz jackets on a regional airport; but not in GA.
For me, airside safety is about staying alert and giving way to the aeroplane, because you have more ability to manoevre on your two feet then lets say a taildragger crabbing down the taxiway. On that basis, I wouldn't consider it a worthwhile investment to buy a jacket.
However, the CFI at my local club obviously disagrees with me, and mandates the wearing of high-viz jackets airside. But at least he does loan them for use without charge, so I can't really complain.