Php to me at least looks more like C or at most C with classes than it does like C++ so that in a way it favors older people. I've never needed classes for anything I've done with Php so the subject hasn't come up.
In C or C++ normally to to do old-fashioned writing and reading of objects or structures of a fixed size, I'd just as soon use structures and fread/fwrite statements, to me at least that's a little bit easier to read.
The problem arises when an object contains pointers to allocated memory and objects can vary in size. C++ IO does not handle that for you; what you'd do normally would be to define << and >> operators which pick up sizes from a header of some sort and then read/write the rest of the object.
I'd assume the main point of any sort of a decent serialization system would be to handle that sort of thing without the need for such metadata in objects.