It doesn't matter that it's optional. The node in the middle doesn't know if it's turned on or not, so it cannot know if it sees the full amount or not. Monero also requires trusting that the other 14 keys are not held by the same entity or cooperate to deanon you. This is true for any privacy system and impossible to avoid. 14 is arguably higher than the usual length of payment path in LN, so I'll give you that but it's stilk not infinite and making LN path 14 nodes long is still possible. You might be in a different social bubble, I've seen many people use Coinomi and recommend it. But that was a long time ago, maybe it has changed. A significant problem with Monero is that it requires scanning whole chain, which will get expensive as more users come, pushing people to send view keys to scanning services. Compared to that, you only need block filters to scan bitcoin and then just handle the channel. The irony of Monero is that the more people use it the more some privacy breaks and other improves.