Presumably, there are circumstances where builtin::stringify() and scalar() are not the same thing ....

I've finally found a difference, though I don't know if it's intended or accidental:

D:\>perl -wle "print scalar(10,20);"
Useless use of a constant (10) in void context at -e line 1.
20

D:\>perl -Mexperimental=builtin -wle "print builtin::stringify(10,20);
+"
Too many arguments for builtin::stringify at -e line 1, near "20)"
Execution of -e aborted due to compilation errors.
[download]

Cheers,
Rob