You have a point.
Maybe there are not real automatic withdrawals, but some casinos I used in the past processed everything really quickly, so I considered them automatic.
For other casinos I had to wait for hours to get withdrawal approved manually, and than I have to wait for blockchain confirmation.
I think it is safer to grade casino withdrawals to Fast, Medium, and Slow, but this is again only average grading.
Manual processing is only for very small business and it needs human to check, approve withdrawal request and proceed it. It takes time, and human needs to rest, sleep so there will be possibly unavailability some times. It's unsure that a company will have different people who serve different shifts so that user withdrawal requests will be checked, approved, and proceeded quickly enough.
It's big disadvantage of manual processing, and big business won't use this method. With automatic processing, there will be problems sometimes but it will mostly be more convenient, time saving than manual processing.
Many times, platforms with one man for everything, manual processing turn to scam. Recently we have Scoras.io casino with the representative account disappeared in about 1 week.