https://blog.bitmex.com/the-lightning-network/Abstract: In this piece, we explain the motivation behind the creation of the Lightning Network and why its scaling characteristics are superior to what we have today, potentially resulting in a transformational improvement. We describe some of the basic technical building blocks that make Lightning possible. We then examine some of its limitations, including the downsides of inferior security compared to transacting on-chain and why this makes Lightning potentially unsuitable for larger-value payments.
Conclusion
In our view, the Lightning Network does appear to potentially offer significant and transformational improvements with respect to scalability. Therefore transaction speeds and transaction fee rates should dramatically improve, without impacting the underlying security of the core protocol. Crucially, however, the inferior security properties related to Lightning payments, may make the Lightning Network unsuitable for larger payments (or at least it may be irresponsible to use it for larger payments). Speculation and investment flows, which require these larger payments, currently appear to be the major driving force in the cryptocurrency space, with the volume of small retail payments being relatively small in comparison. Because of that, Lightning may not be as big of a game changer as some imagine, at least in the medium term. While enthusiasts appear likely to adopt this technology quickly, widespread adoption may take considerable time.
Great text about Lightning Network write by the Bitmex Research Team.