The tricky part is the actual demand may arrive someday with nothing in place to serve it as all of it was abandoned years ago
Yeah.
There is a cryptocurrency giftcard site in the UK that I buy supermarket giftcard top-ups from regularly, always paying in alts, simply because I want to keep the alt option going. (I'm scared if no-one uses it, it will get disabled).
Here it is:
https://www.cryptodechange.com/As far as I can tell it's the only giftcard site in the UK that accepts litecoin and doge. And these things are very much "use it or lose it".