I recently got bit by a subtle bug.

char ** int2str = {
   "zero", // 0
   "one",  // 1
   "two"   // 2
   "three",// 3
   nullptr };

assert( values[1] == "one"_s ); // passes
assert( values[2] == "two"_s ); // fails

If you have godlike code review powers you'll notice I forgot the , after "two".

After the considerable effort to find that bug I've got to ask why would anyone ever want this behavior?

I can see how this might be useful for macro magic, but then why is this a "feature" in a modern language like python?

Have you ever used string literal concatenation in production code?