link: https://eips.ethereum.org/EIPS/eip-3

IMO it's a good practice to check return value of callee if consequential operations is dependent and critical, if so what's the advantage of checking CALLDEPTH instead of return value?

Another point is, even if you use CALLDEPTH to guard stack overflow, you may still need return value guard in case there's other errors, thus leads to more verbose code?