This is a simple question, but the answer is not easy to find if you don't test by yourself, because it is partly a pyramid scheme and users encourage you to use it expecting referral rewards.

So i have done the test, using at the most the offline cashback, but i had to top up my account at a time because they didn't accept my receipts when the advertising budget was over and the pending cashback at zero. I sent unwillingly 10$ worth of ETH.

It was a long run, more than 2 month but i succeeded to withdraw the minimal amount of 100$:

And i received it on my account about 12h later (it was quite stressing):

The amount is fair as i took a snapshot of the converter at the withdrawal time:

Following the blockchain explorer, i saw that they paid nearly 2 BTC in that batch payment, you can see it HERE 

So i can say the answer is YES they pay !

For other questions like is it a good investment ? is it risky ? I'm not an advisor, i just give the facts.

If you are interested in trying AI.MARKETING you can use my 50$ gift certificate to top up your account: 05ST-XPVJ-QN9J-JC4K (or the thousand others you can find on the net), but you need to know that you'll have to give them back prior to withdraw and the first withdrawal is 100$ minimal. As the expected return is around 73$ for 50$ you probably won't be able to get some money without investing a bit, even if you use the offline cashback. I didn't try the online cashback maybe it is a better way.