Earlier this year, Wizards of the Coast made a transition, moving most of their logins and player data into a unified system called “Wizards Accounts”. This transition included the moving of all tournament information (match history, DCI number, Planeswalker Points) into this new system.
This transition also had several behind-the-scenes changes for events. For example, if you go to a new store and forget your DCI number, the search tool that the store will use will search for information based on what’s in your Wizards Account. If that account does not exist, the store will not find your DCI number. Similarly, if you register online for a Grand Prix or other tournament, and you mistype your DCI number, the only way for me to fix that is if I can find your actual DCI number somewhere; if I can’t find it and you have byes, then those byes aren’t automatically applied, and you’re coming up Saturday morning asking why you lost the first round when you were expecting byes.
And those aren’t fun fixes for me, either.
Some other reasons that you should have a Wizards Account:
Your byes are automatically applied only if your DCI# is associated with a Wizards Account. If you don’t have a Wizards Account, we may not be able to associate your DCI# to your byes.
If you win a prize from Wizards at a Premier Event, (GPs, PTs, etc.) Wizards will be contacting you via the email address of the Wizards Account associated with your DCI number.
Qualifier lists for events like Nationals use the information in your Wizards Account to help derive your qualifications. If you don’t have a Wizards Account, you won’t show up as being qualified for these events.
If you don’t have one, I would highly recommend signing up for one at the Wizards Accounts site.