I would point out two main issues: 1. Such a string cannot contain arbitrary bytes. Since it is frequently useful to work with arrays of arbitrary bytes, we ha

I would point out two main issues: 1. Such a string cannot contain arbitrary bytes. Since it is frequently useful to work with arrays of arbitrary bytes, we have to repeat every library function twice, once for strings that can contain nuls (the mem* series of functions), and once for strings terminated by nuls (the str* series of functions). The latter are much better supported, and are easier to work with, so we frequently see programs that trip over strings with nuls in them for no particularly good reason. 2. We often want to modify strings, not just read them. Modifications often need more space than was in the original string. A nul terminated string cannot say how much room beyond the current length is allowed to be written to. By default, most library functions assume that there is enough space, however this is frequently an unsafe assumption. This again causes us to duplicate every library function twice over in order to specify the size of the buffer (the strn* series of functions). Since, again, these functions are poorly supported and harder to use, we see many many instances of programs that have buffer overflow bugs, and therefore likely RCEs, for no good reason at all.