I tried a few times to read about the Lightning Network and it seems complicated to understand and implement. I'm not an expert at all but it seems like a flaw in the Bitcoin protocol that you have to build something like this on top.

Are there other cryptocoins that are built on protocols that avoid having to have this extra layer on top to make them scalable? I imagine the more complexity that is added, the more scope there is for security, implementation and scalability issues so you want to keep things simple.