Stack overflow on a hosted operating system is an event. A guard page is hit, the process receives a signal, the debugger stops on the offending frame, and you have a stack trace pointing at the recursion you forgot to bound. Stack overflow on a bare-metal Cortex-M is not an event. It is a silent write to a variable that belongs to something else, discovered later, in code that is innocent.
A null-pointer write on a Cortex-M does not crash. Address 0x00000000 is real memory — it is the start of flash, or the boot alias — so *(uint32t )0 = 42 on a fresh chip silently does nothing at all, and the program carries on. A stack that overflows its intended region does not crash either; it grows down into .bss and corrupts variables that belong to something else, and the failure surfaces minutes later in code that is entirely innocent. Both are the same problem: on a bare Cortex-M, memory has no permissions, so a wrong access is indistinguishable from a right one.*