Is there any practical difference between transferring ownership of the trademark to Automattic vs. granting them an exclusive license that they're able to sublicense?

The only major difference I can think of would be that the license to A8C could be revocable. But that doesn't make any practical difference, especially since A8C / WPOrg have a hand-in-glove relationship.

A8C is still a for-profit company, if it's sold in the future, and the new owners aren't behaving correctly, the trademark can be revoked.

Apparently it was an irrevocable grant.

As I understand it, WordPress Foundation's board can revoke the license if Automattic is no longer a good custodian of the brand.

It makes sure even if Automattic is no longer in good hands, the Foundation can protect the WordPress brand from Automattic.

(I work at Automattic but did not specifically checked the details of the trademark agreement)

The lawsuit asserts pretty vehemently that it's "irrevocable."

It quite literally states in the document that the trademark is irrevocable

Which document are you referring to?

Have a look at the trademark assignment document filed with the United States Patent and Trademark Office:

https://tsdr.uspto.gov/caseviewer/assignments?caseId=7882673...

Thanks! I read plenty of patents and lawsuits but haven't had to look up a trademark before.

as I understand it the foundation board is matt and two people matt chose.