I mean does it slows down the FPS or is badly optimized ?
It’s for anti-cheat purposes
It depends on the device and OS, here is the list where each of them stores it:
During my tests calling it at least once per update did not have any effect on performance.
The best thing to do actually is to check your data online rather than offline. And if your game is offline only, I wouldn’t bother with anti-cheating so much.