Biblical apologetics is a form of evangelism (1 Pet 3:15), and not a form of polemics. Also, Biblical apologetics technically has nothing to do with philosophical argument. However, in practice, the term apologetics is traditionally used to refer to principles and arguments for defending the faith. But more precisely, these are two separate categories. The first (Biblical) is simple evangelism, and the second (arguments) is more philosophical.
Of course, I think it is vital that Christians use their brains and do philosophy, but doing philosophy isn’t the same thing as evangelism. Both are needed, but for different reasons and in different contexts.