Question to the world: what is the EXACT state of play in offline transactions right NOW?
Can I do an offline transaction, even if only as a proof of payment, today - or is more work needed to be done.
Many thanks plebberoos.
Discussion
You can use a satscard or opendime, maybe ecash can do such stuff too in a way?
Chaumian mint based ecash requires connecting to the mint to transfer ownership of tokens. You could pass them around offline, but not trustlessly.
I am only aware of hardware solutions for true offline transactions - coinkites opendime, etc.
You could do it with payment channels (eg. Lightning ) but you would need to go online at some point to confirm the channel wasn't closed and potentially publish a revocation tx.