I have to admit that I feel that way myself. That's why I removed them, but it was source of residual income. I now have to wait and see what happens with regard to the number of enquiries coming in.
I run a small consultancy where a successful conversion of a basic enquiry could earn me an amount close to one months Adsense earnings. A really good sale, which does not happen often, could earn me up to one year's Adsense income. That's why I decided to try this.