Had a random thought after rewatching Tenet: #Bitcoin is backwards time travel resistant. 

In the movie, people from the future fund the villian Sator's plans by sending gold bars back in time. This is possible since gold is physical.

But if someone were to theoretically do the same thing and buy up some sats, load them up into a wallet, and travel back in time, he would no longer have those sats.

When he travels back, his wallet will synchronize to the chain of the past, which hasn't yet confirmed the future transaction the time traveler made to load up his wallet.