This is Google AdWords 101.
Ad position is determined in part by CTR and in part by your maximum bid. Relevance improves your campaign's economics, all things being equal.
However you can make NO blanket assumptions about conversion rates or ROI from higher or lower CTR's. Post-click behavior varies too much.
CTR's can be goosed with free offers, enticing copy, etc. Similarly, CTR's may go down when you prequalify prospects with your copy (making sure people know it's a fairly sophisticated or expensive product, for example).
I would pursue high CTR, but not at the expense of ROI, i.e. if there is a way of writing your ads to weed out non-buyers, you should probably do so in spite of the likely drop in CTR. It's a judgment call, really.
If you want to amass a large number of leads no matter what, you might for example want to attract them with a free white paper and then continue to try to sell them on something later. But is it worth paying (again f'rinstance) $1.60 a click which converts to a lead 5% of the time for a total cost per lead of $32? Only you know for sure.
High CTR's are not the holy grail. It's nice that Google rewards them, though. It means advertisers don't have as much incentive to blanket the space with low-CTR ads for branding purposes, and it makes the marketplace more open to the small, focused advertiser.