Oh shit, that's so simple and so elegant. How many people even have a working. Cassette player these days? Genius. And anyone under 30 won't even recognise what they're looking at anyway 😂 What's the lifetime for tape though? It degrades over time even if it's just left sealed away, doesn't it?
Discussion
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.