I do not think there are any adverse effects associated with this setting. I actually spent a good portion of the day searching for why usbcore.autosuspend causes the machine to wake up immediately.
The only thing I could come up with is that autosuspend tries to suspend a USB device only to have the USB device "wake up" after the computer was in standby. This would cause the system to resume because of the USB wakeup. I have no idea if that is the reason, but it is my best guess.
This link talks about usbcore.autosuspend: http://lwn.net/Articles/253587/
Also, adding the line
to /etc/modprobe.d/options is a method to disable without messing with your bootloader.