What people critizing this seem to miss is that it's exactly the same situation as for SSDs which include hardware full disk encryption (FDE): If the processor

What people critizing this seem to miss is that it's exactly the same situation as for SSDs which include hardware full disk encryption (FDE): If the processor inside the SSD responsible for encryption/decryption breaks, you can't recover the data as well anymore. What would be the processor inside the SSD is the T2 chip in the current MBP's. It even exposes the same interface (NVMe) to the rest of the system as the processor of an SSD does. The only differences are that the T2 chip has some additional responsibilities in addition to handle the storage and its encryption and that the die with the T2 chip and the flash chips is larger (as it's the motherboard) and might not be as sealed against environmental impacts as the one of an SSD (which could be a higher risk of failure).