The problem is that when using Apple Intelligence as a user, you never know when the OS will send your query to Apple Private Cloud instead of processing it with an on-device model. As far as I can tell, there is no way to keep Apple Intelligence enabled and at the same time disable automatically routing requests to APC if the OS deems the query is too complex to be processes locally. There simply isn't a single warning pop-up before your request gets sent to APC.