Hans,
i know exactly what you mean.
but, once you got the technology (aka algorithm) you can add as many details and features you like.
this is what makes computing stairs so nice:
they are multiple things from the same size. So letting them turning around in a spiral, containing little details on every step, with a nice curved handrail, all that or (even more) can be calculated. and, while this staircase would be created all at once, there is less chance for an error.
now when i download some stairs, i need to rescale them, which loooks awfull and wrong. the resulting picture is (for my needs) useless. i'll go for the real pix with a constructed one from a 3d programm.
for test renders the mentioned block-approach is quite good-i could even add a handrail, i think
