Even if the site isn't using a CPM model, getting paid by views, ad impressions still count towards getting better ad deals. For example when dealing with private ad-sales. some people also use ad impressions to count pageviews, for example with Adsense, if you have 3 ad-units on one page, they count as one pageview.

Although, having a huge technical audience who doesn't click any ads will greatly decrease the CTR which will affect the eCPM the publisher is getting paid.