Quick page loads
Easier development and maintenance
Some JS libraries are more niche. Rendr is an additional Airbnb-made library that focuses on isomorphic data structures. The Airbnb mobile web app, which features extremely fast page loads thanks to Rendr, was built using Backbone.js and Handlebars.js, two of the most popular single-page app frameworks.
Because of its ability to remain a library rather than a framework, Rendr can be integrated into your stack in whatever way you see fit and offers more flexibility than a comprehensive option like Meteor.
Final word on whether isomorphic programming is still a thing