Yup, but the difference is that some of your appreciating asset is being paid for by someone else. In some cases that's worthless, in others quite valuable.
Yes, investments involve risk. If you believe that another cataclysmic crash is coming to the real estate market, then stay out. If you think it's unlikely, it can be a relatively low risk investment for the returns.
When it goes wrong, it fails catastrophically.
That is to say, the variance of slumlording and poker arr probably equal :)