If the advertiser used the same bids on different properties, the campaign wasn't yet set up well. Also the device (mobile/desktop/tablet), query, language and

If the advertiser used the same bids on different properties, the campaign wasn't yet set up well. Also the device (mobile/desktop/tablet), query, language and many other features of the user session change the conversion rate, which means the bid should be different. The fact that the ads were useless meant that either there is too much auction pressure and the advertiser wasn't able to compete, or he just didn't set up the campaign well (which is of course a hard task). It would be good to know if the advertiser was using Enhanced CPC or not, which can increase the effectiveness of the ads, but even then it takes money to set up the bids correctly. Disclaimer: I'm working on a relevant product