Here is a quote from the FamilySearch Blog:
“One of our goals at FamilySearch is to create a research experience that is fast and efficient. That’s why, when you visit our site or use our app, you come across so many different tools. You can attach photos, list sources, use record hints, and search partner sites, and the list goes on.
“However, in some cases, you might have limited internet bandwidth that doesn’t allow all the bells and whistles of the website to run smoothly. Or maybe you simply want to save on data usage. For these circumstances, we have created a streamlined version of FamilySearch’s Family Tree, known appropriately as Family Tree Lite.”
You can read a lot more about Family Tree Lite at: https://www.familysearch.org/blog/en/family-tree-lite/.