I don't think it's slippery. A friend of mine put in real linoleum floors in her kitchen a couple of years ago, which is made with linseed oil and other "stuff" - the brand was Marmoleum. Two weekends ago, she did her first maintenance on it (you don't have to do anything to it for two or three years), which is to clean it really well, let it dry and then put linseed oil on it. I was there this past weekend and it wasn't slippery at all. I don't feel it's a wax, more of like a conditioner.
I don't understand putting it on brickwork, though. Like you said, the brick/stone is porous, so what's the point? I googled to see if there were any applications for it being done this way and while there were several hits that said you could use a mixture of turpentine and linseed oil on bricks, stone and concrete, I couldn't really find a tutorial to explain why you'd do this versus some other product. Plenty of them talking about using it to rejuvenate a wood floor, but nothing really explaining why you'd do so on anything else. I couldn't even find something to explain why you'd use a mixture of linseed oil and turpentine - most of the tutorials were using a ready made product.