(maybe the examples I provided are not ugly enough to show difference, so I'll try to do that here)
On non-rest API you can get in trouble mixing actions and resources, so you can get things like
{'action': 'list_users'}, {'action': 'rename_user'}, {'action': 'user_ban'}, {'action': 'rename_user_and_email'}, {'action': 'list_active_users'}
While on REST API you are at least consistent that user-resource is /users/, that concrete user is /users/<user_id> and that only operations are CRUD on either all users -> /users/ or on concrete user /users/<user_id>. That gives so much more clarity (+ caching reads, + only open transactions on POST/PUT/DELETE).
On non-rest API you can get in trouble mixing actions and resources, so you can get things like {'action': 'list_users'}, {'action': 'rename_user'}, {'action': 'user_ban'}, {'action': 'rename_user_and_email'}, {'action': 'list_active_users'}
While on REST API you are at least consistent that user-resource is /users/, that concrete user is /users/<user_id> and that only operations are CRUD on either all users -> /users/ or on concrete user /users/<user_id>. That gives so much more clarity (+ caching reads, + only open transactions on POST/PUT/DELETE).