At the end of the day, Maple, like Apple (in nearly all cases), is performing their compute on plain text queries. Using secure boot and secure enclaves and other techniques to try and prevent adversaries (or themselves) from looking at those plain text queries is simply not (and will never be) the same as mathematically protecting that data with strong encryption.
It is still a worthwhile effort to protect their users that will provide more security than OpenAI and other AI companies just running on GPU servers that any of their employees can access.
It is also still essentially a pinky promise that they have implemented all these security measures correctly (which I would not necessarily take for granted given the complexity required of these setups), and it doesn’t make sense to treat it much differently than VPN companies claiming they’re using disk-less setups and not logging.