If I wanted to go nuclear with certain pieces of data, how reliable are WORM SD cards?

Not sure how else to flair this. But here goes.

If there are certain pieces of information I wish to keep very secure, as in unchangeable, and I wanted to go the nuclear route, how reliable are WORM cards?

I know it means Write Once Read Many, but how true is that? And if it is very true, can the data ever be extracted (or copied) from the SD card and put elsewhere? How much of a wall surrounds that …

data goes information nuclear privacy worm