KeeperFX has a different file structure than DK Gold/GOG, so you can't just use this pack as is. KeeperFX supports custom campaigns, while the original had just the single campaign and user made ones where made the overwrite the default one.
This can be easily solved by making a campaign-config for this campaign, but this pack also comes with a 'creature.txt' file which contains all configuration files in one for all units and rules. It modifies the heroes and their attraction requirements. (And more). KeeperFX has a separate config file for every unit and magic and whatnot, so making those files would be lots of manual labor.
So simply put, too much work. If you do want to, there's a wiki page on how to make campaigns for KeeperFX here: https://github.com/dkfans/keeperfx/wiki/Creating-a-new-campaign