You read it right.
Atlanta will eventually get a team, and they very well may be the next expansion team. But, with the NHL and Houston far apart on numbers and no apparent momentum to get closer, Phoenix basically dead in the water for now, and every other potential market having holes and "if's" attached to it, Atlanta will be a threat. I don't see the league expanding to 33 teams without a short-term plan to add #34, and I don't see them going out on any limbs to award #34.
The threat is even bigger if there is an arena either waiting, underway, or approved and just waiting for a tenant to start construction since the "or else" part of the threat can be implemented pretty quickly.
For a professional sports league or team owner, having one or two strong markets asking for teams is a powerful weapon. From their perspective, it's a lot better to have more demand than supply, rather than looking like you have more supply than demand (the Coyotes situation prior to the move).
Atlanta is also a bigger caliber weapon for that purpose than KC was, or QC has been.