Only if people actually click on competitor ads. I imagine it's pretty rare anyone searches for ebay and clicks on amazon ads instead. So you're uniquely situat

Only if people actually click on competitor ads. I imagine it's pretty rare anyone searches for ebay and clicks on amazon ads instead. So you're uniquely situated to outbid the competition with absurdly low CPC because click through rate is dramatically higher. And sure, it's not fun handing over money to defend your brand. I could see an argument be made that you want the competitors to outbid you because the costs are so high for them.