I wonder just how often Ferengi would use Eliminators against each other. Given their culture, setting a Liquidator against your competition could be seen as far worse than just getting killed, since a Liquidator not only can destroy you, but your family and you then have to live with the shame or even worse in poverty.
An Eliminator would be great for non-Ferengi competition as they don't fall under the FCA, so you can't set the Liquidators on them.
Anyway, it was an enjoyable episode. You have to wonder what Starfleet was hoping to get for giving Quark Keevan since they had no idea (or would even suspect) the Ferengi would get a new Vorta. I guess if Quark told them about Ishka and Zek Starfleet Command thought it would be a good way to seek the Grand Nagus' favour, maybe sway them into aiding in the war against the Dominion.