Because the tiny11 in 100pc quantities was only 25 cents each. That's four for the price of one... Pin for pin, mhz for mhz it's impossible to find anything that small useful and easy to program for less money. You can get some PICs for near that price but they're old ones, crippled chips compared to an AVR. I knew I should have bought 100 of them when they were still available in stock at Digikey. They're just absolutely perfect for LED drivers and fast enough for many glue logic apps, and many other things, and best of all I have a programmer and have used them before. I like them best for LEDs, because at 5 volts the output drivers are current limited so they can be attached directly to RGB LEDs with no other components after a simple calibration. I still have about a dozen left, but when you're talking about larger scale 'intelligent' projects the cost per chip is really important, and it's hard to beat a tiny11 costing 25 cents.