So far, Salesforce relied on its own programming model Aura, which,
however, has a much lower prevalence compared to Web components.
The company brought Aura into the game as Lightning was launched
because there was no clear standard for creating large client-side
Salesforce Lightning: Integrated with existing offers
The announcement states that the approximately 70 Lightning Web Components give developers the freedom to use the tools they like to use to create components – reusable building blocks for building Lightning applications. Using these Web Components in conjunction with other developer services, such as Lightning Data Service, Lightning Locker, and Base Lightning Components, as well as Salesforce’s low-code tools such as Salesforce DX, Lightning App Builder, and Lightning Flow, allow companies to leverage their developer and admin resources better use.
A detailed introduction of the Lightning Web Components interested in an article on salesforce.com . They will be available in spring 2019 as part of the next major Salesforce platform release.