function ref param vs pointer param

[ref2401 via Digitalmars-d-learn]

What advantages do ref params give over pointer params?

struct MyStruct {
	string str;

	this(string str) { this.str = str; }
}

void processRef(ref MyStruct ms) {
	writeln("processRef: ", ms);
}

void processPointer(MyStruct* ms) {
	writeln("processPointer: ", *ms);
}

void main(string[] args) {
	auto ms = MyStruct("the ultimate answer to everythin is the 
number 42");

	processRef(ms);
	processPointer(&ms);
}