I was watching this video: https://www.youtube.com/watch?v=gHGMDFm2MVs in which it is suggested to use memset_s() to avoid any issues because of compiler optimizations.
Also explained here: https://stackoverflow.com/questions/56565539/memset-s-what-does-the-standard-mean-with-this-piece-of-text
It is used at lot of places: https://github.com/search?l=&q=memset+repo%3Abitcoin%2Fbitcoin&type=code
Should we replace it with memset_s() ?
Bitcoin uses the memory_cleanse function in its stead.
The memset_s function is defined in C11. Bitcoin Core isn't written in C, but in C++. No C++ standard to date includes such a function.
Furthermore, it's an optional part of C11 which most compilers haven't implemented even; specifically, none of the compilers used for Bitcoin Core's release builds support it.
Lastly, Bitcoin Core has its own (best effort) solution to clearing sensitive memory: an ad-hoc implemented memory_cleanse function which uses a technique to avoid being optimized away. We certainly wouldn't want all memset calls to be replaced with such a security-hardened version; most uses of memory setting are not used for clearing sensitive data.