The points system doesn't protect our borders against illegal immigration. By definition, it's illegal and won't be subjected to any system.
Market forces already mean that the majority of people coming to the country (especially those from the EU) are those whom "the country needs". The UK has always had total control of people coming from non-EU countries. The majority of immigration has always been from non-EU countries.
People from the EU come to the UK to find work, so therefore contribute to the economy. They are generally young and hard-working and contribute more, on average, to the economy in taxes and NI contributions than those born in the UK, quite apart from the valuable work they do.