Credit Casino System is the accounting system between the player and casino provider which managed by agent/junket manually transfer credit for gambling purpose
Cash Casino System is the website system which integrated with games api , works between player and casino provider , player need to transfer cash to the system first in order to reload the gambling credit
From Front end website. Credit Casino Website only has basic function to reach the Contact Person and communicate the user detail, payment offline.
For Cash casino website, all the user registration, payment will be handled in the website like ecommerce, no live human directly manually handle the details. But most online casino will have live chat support to handle any inquiries.