I personally don't think it's worth the risk. I've used Cdkeys once or twice myself then learned more about it and other similar sites. No, nothing has happened to my Origin or Steam account but I've seen others effected by chargebacks before. Just because someone has used it many times doesn't mean your accounts not at risk even a year later. I fully aware my account is still at risk and those I bought codes for. Now I know better and I'll wait for sales if I must.
*shrugs* Totally up to you. When your account gets locked after a chargeback, you can open a case with Origin to have them undo it. (If whoever's helping feels nice) Steam is more strict.