It backfired when I tried to open a Lightning Network channel with a low fee, and the channel was closed when it didn't confirm within 24 hours. Closing the channel meant a much higher fee did CPFP.

Talking about LN: is that a subject here in WO? I only follow this thread once in a while (there's just too much to read), but considering the level of Bitcoin fans here, I'm curious if it's used