It is legal but redundant to refer to members through the this pointer. Discuss the pros and cons of explicitly using the this pointer to access members

It is legal but redundant to refer to members through the this pointer. Discuss the pros and cons of explicitly using the this pointer to access members. 

struct First { int memi; int getMem();
};
struct Second {
 int memi; int getMem();
};
First obj1;
Second obj2 = obj1; // error: obj1 and obj2 have different types