Rebate debate

I'm in the middle of submitting a few rebates online for some computer parts for a computer I'm building for a friend. The website noted 'submit your rebate online! get your rebate check faster! blah blah blah'. I proceeded through the steps for submitting them online. I get a confirmation email and to put the code in to proceed with the process. I get to it, and then it says that I need to print out and submit corresponding copy of receipt, etc. As Stuie would say, "What the deuce?"

What's the point of submitting for a rebate online and then have to still mail in the stuff the normal way? Probably just another annoying tactic for consumers to not submit for a rebate and lose that money that is due them.