The blob is the low-level wireless firmware, and regulatory rules make it obligatory. When you use the ESP32 as a dumb modem in conjunction with a separate MCU, you‘re still running the blob. You have gained nothing.
You have isolated it into its own (not even virtual) machine. Any buffer overflows or whatever won’t spill over.
True, and I‘ll buy that argument if your main firmware is memory safe (Rust, verified C or smth else without an unsafe C runtime underneath). Otherwise its just mine vs someone else’s C, and people have traditionally been overconfident on theirs.
Strong isolation gives fault tolerance not otherwise available, no matter the language. If one part crashes, the other part is not necessarily affected, unlike the situation without good isolation.