The Lightning Experience framework allows your organization to exploit the latest cloud-based features that modern applications offer today.
Modern application include responsive user navigation and visually attractive user interfaces that are present in the Lightning application that is not technically possible within the Classic themes.
New features have been introduced within Lightning Experience that were previously only possible by using additional customization in Classic. As an example, when users create new records, it is often good to pre-populate fields with common data to prevent users from having to enter time-consuming data. These customizations, sometimes not supported by Salesforce and referred to as hacks, are not necessary for Lightning Experience since this functionality is included as standard.
It is also possible...