Jordan,

I don't agree. It is not 'extremely difficult' to make money promoting Clickbank products on Adwords.

The problem seems to be that many people think if they take any product and then try to promote it with the most obvious, generic keywords they should be making money and if they don't they say 'Adwords doesn't work'.
Also, many of theme never bother reading the Adwords Terms & Conditions

Adwords does work very well - it also works from promoting Clickbank products - even with direct linking.
You just need to pick the right keywords.

Honestly, I have some direct linking campaigns that I have not changed for one year. Some of them get back 3-4 times their advertising costs.
And when I check I can hardly see any competition, because everyone seems to be advertising in the same keywords.

You just need to be very selective.

There are many good products on clickbank besides all these scam offers.
Pick a good product and find some keywords the other affiliates are not using.
Then you can make some serious money!