I disagree with this comment in the article, or suggest it could be more carefully written.
If you’ve credit card debt to shift, act now before deals worsen.
If someone has an existing card balance they are considering transferring, then if it is interest bearing then it was already worth acting before this.
However someone who has a balance already at 0% and wants to move it in a few months time should note this but not panic. Voluntarily losing say 6 months now by transferring early would be worthwhile only if more than 6 months will be trimmed from new deal availability within that time. Is MSE suggesting that might happen? Not necessarily.