RGB LN supporting offline payments proposal

[UkolovaOlga]

Introduced by @tkachuk-labs in RGB telegram chat:

"Idea about hypothetical standard for offline LN payments, which looks relatively simple, but I didn't find implementation - so I assume I missed some reasons why this can't work."
https://tkachuklabs.gitlab.io/blog/2020-10-23-offline-lightning-wallet.html

[St333p]

I gave a quick read to the proposal and here are my feelings.

If technically this could totally work, the lack of interest for this protocol might come from the business side. I don't really see a real customer space for this kind of service, at least not until home LN nodes become widespread. This might make it very difficult to bootstrap such a system to a level of diffusion that makes it practical to use. Some reasons that come to my mind at first sight are:

• convincing merchants to accept crypto is hard, only really doable if the effort from their side is not more than the one required with paper money or cards. This is a very cultural thing and thus really difficult to change: some countries are still struggling with cash -> cards transition.
• the interactive process at payment is potentially quite long (10-30 secs?), even not considering human verification of preimages (not very user-friendly). The PIN thing would make it even longer and less friendly
• owning a smartphone is way more common than having a printer at home
• there is quite a bit of effort and time involved for people, that need to think beforehand what they will need, go through some software to create and print bills. We are in a world where people use google pay because of the effort required to carry a bank card around.
• security focused individuals that would not trust smartphones for day-to-day payments are very few, and they still can set
  "smartphone spending limits" if their mobile wallet connects to a home node (in this case no special support is needed from merchant side)
  -> As a result, building the market is difficult: merchants will not spend effort to offer this feature until it's a widespread mean of payment, and people will not start printing bills until there are many merchants around that accept them

Still, I'm very ignorant on the business side of things, so if anybody sees potential in this proposal I'm totally in for discussing technicalities and protocol details or improvements.