The magnetic properties of tape can fade. But it's an analog signal so it will fade but not disappear. If taken care of, I still buy tapes over 40 years old and I think they sound great.

However, strong magnets can erase them. This is a pro and a con.

At CES, _this year_, a major music electronic producer called Fiio released a brand new walkman with usb c charging.

So, yeah it's niche. But I don't think it's going to 0.

And yes, it has the obfuscstion properties you mentioned.

I'm experimenting with a pencil and paper encryption scheme based on a one time pad, but honestly just Shakir split on multiple tapes might be easier.