That is now an absolute last resort. It rarely helps these days. There are other ways to correct corrupted files such as using the Scan and Repair tool on the launcher.
The steps that I would suggest if someone is getting an instant DC on one char:
- Use the self-service STUCK service. It can be done from an alt in-game, or done here on the website.
- If that does not work, consider there may be addon or UI issues - that is a common cause of this. To rule that out, a person would do a full UI reset, not just disable addons. They want to start the game without those files at all to see if it helps. https://us.battle.net/support/en/article/7549
- WAIT for an instance to reset if that is where you got DCed. It usually takes about 30 mins for a soft reset, but can take longer.
- If all else fails, use the ticket link that CS gave to the OP for a GM to manually intervene on a STUCK case.
In this case the OP did post in CS and was given the correct ticket information link. Hopefully they are sorted already.