Biggest benefit is to fetch data on need basis.. lets say you have Jira system that has all the story information, now in ServiceNow you want to validate if a given task number is valid, you can create a choice list that runs on remote table and verifies if task number is valid, tat way you are not storing data in ServiceNow, instead only getting info as needed.
There are other usecases if remote table runs on a ServiceNow instance..
caution / note : remote tables will consume integration hub transactions
