In answer to the original question (which didn't identify forex as the field of interest - and which is an area I don't do) - I would say that for a beginner, spreadbetting is an unsafe route. Familiarising onesself with the market behaviour of the product (be it forex, stocks, whatever) is surely best done without throwing in the drama that leverage can create.
For the non-beginner, ie someone already familiar with the product and how it behaves, then yes - spreadbetting has advantages over plain dealing.
I am now into my 10th year of trading shares for a living (UK only. Mainly mid-caps). I began with conventional share trading and still do some, mainly within PEP and ISA accounts. But nowadays the bulk of my gains come from sbetting which I find far more convenient. So much so that I would give up conventional trading altogether now, were it not for the risk that the rules might get changed sometime, making sbetting less advantageous. I would not wish to find myself with no ongoing PEP/ISA investments.
In the first few weeks of 2007 I have banked enough in sbet winnings to live off for about the next 18 months. I could not do that from the same capital base by conventional means. And although using sbets does mean employing risky leverage, the speed with which (prudently selected) positions can generate gains, means I can snap the position closed and stand aside. I don't have to weather all the ups and downs and ongoing worry that can affect a longterm holding.