As far I know (from docs) the lightning network is not centralized.
Well, I consider the Lightning Network somewhat centralized simply because you're going to need to trust LN nodes on the network to route your payments.
People often seem to conflate trust with centralisation. They're different concepts. LN is undoubtedly a different trust model to regular, on-chain, Bitcoin transactions, but that doesn't mean it's centralised. It's still a peer-to-peer network. There's no central authority making stuff happen.
Not to mention, not everyone will be able to open/close channels on the network, allowing only banks and wealthy institutions to operate LN nodes.
Yeah, I'm as confused by this point as Wind-FURY, you're going to have to explain how you've arrived at that conclusion. If anything, Lightning is better suited to small payments than it is large ones. At the time of writing, the most you can send in a single payment is ~$280 USD. Literally the
only thing stopping people from running LN nodes is that they don't understand it yet. You don't have to be wealthy to do that (although, obviously you have to have
some funds). And you certainly don't have to be a bank. Once you have more knowledge, you can take part and open/close as many channels as you wish.