The Cardinals have another buyer on the trade market
This deadline was already a market that lacked the supply to meet demand. About half the league has a reasonable argument for being buyers at the deadline with a few other teams having fringe playoff chances as well. There are only a few teams that are surefire sellers this year and the Cardinals are among them.
With the Angels deciding to ignore the fact that their playoff odds aren't the best in a brutal division and AL wild card race and make a strong push for the playoffs, yet another team has been added to the demand side of the equation and it sure doesn't seem like LA is done after last night's move.
Having another aggressive buyer on the market means a couple things for St. Louis. One, the Angels have already decreased the available player supply on the market by snagging including arguably the best starting pitcher rental available in Giolito. Second, it creates another avenue for St. Louis to make deals outside of the Cardinals' division and league which always makes things easier.
Finally, with the seal finally broken and a big deal getting done, the Giolito trade should be the domino that finally starts creating some urgency this trade season. For a while, it has seemed like the entire league was staring at each other waiting for someone to blink. Now that the Angels have struck, teams are having their hands forced and are going to have to start being aggressive sooner than they may have liked.
For a seller like the Cardinals, that means they can start cashing in on contenders' desperation to get a deal done.