Hi MiR:
I'm sorry for any inconvenience. I'm not totally sure about the reason for no downloading: it may have something to do with the cost of bandwidth, etc. I'll defer to Shrapnel as far as official reasons.
Anyhow, I certainly hope that you consider purchasing the game. It should arrive to you in just a few days after ordering, you'll get a very cool custom designed DVD case and printed manual with your purchase, and I would certainly like to have you as a customer.
Thanks!