The visit of attribute and field

In kind in visit a field through attribute, what distinction does the field have with direct visit? These additional function are called, can increase systematic expenditure, bring about function to drop? It is same actually, with attribute can better will enclose code, let an user can be used only by your requirement, avoid an user to abuse your field thereby, this bits of expense won't be too much, it is worthiness. Attribute can be bound calm