> Instead of using sidechains, just use channel factories.

I am not familiar enough with the latest advancements in this field. Is it possible using LN/channel factories to achieve off-line-like participation user experience without previous registration with any kind of gateway provider? For example, can you go online, join the network [somehow instantly], generate address/invoice and then put it somewhere for others to later use it when you are off-line? Can you also participate while being off-line for very long periods of time without relying on third party providers to secure your channels? If not, is using sidechains really equally replaceable with LN/CF constructions?