The most common use for exact match keyword domains is to forward directly to an existing website. This is a preferred option as it allows the owner the freedom and possibility to run marketing campaigns, displaying and directing users to their exact match domain name which directly forwards to their existing website. This gives the benefit of the audience seeing the new exact match domain name in the marketing or ads and gain instant recognition and confidence that that company is a good match for their requirements whilst confidently suggesting they are a dominant player in that industry by holding such an exact match domain name.
The domain forward option offers the above mentioned great marketing benefits and opportunities when used in this manner and has no negative effect to any SEO matters.
Of course, if taking advantage of the obvious SEO opportunities by holding such exact match domain names, and new site or campaign landing page can be built and used with the new domain names.