Although, yes, you are correct in saying ROI should be the overiding objective – you do still need CTR to be high – there is a balance you need to acheive.
With the QS algorithm taking into account CTR of the ad – if your CTR is pony(although perhaps converting well), you will end up losing ad rank, paying a higher min CPC which then will damage your ROI also.

Increasing your ROI is all well and good but increasing volume of sales is also important.

The strategy here may only be serving to make it more efficient, spending less and reducing the volume slightly on overall sales.

From a marketing company or PPC agency, where commission made is off the back of clients spend – there is a trade off and conflict of interests in some respects.

Thoughts?

After having great click-thru rates on our PPC ad, with low conversions, we’re concerned that the issue is not in the marketing but in the expectation of the searcher. For example, someone searching for a book on sexual harassment training is presented with an Amazon ad. The searcher may have automatically expected a book like that on Amazon to be priced $15-$25 range. However, clicking-thru, they see this is actually a professional compliance guide that’s priced at $49.99.

I’m thinking, put the $49.99 right there on the ad, to prequalify shoppers who might have clicked thru and left because of the price.