Joining the CPTPP couldn't have been done while a part of the EU, and it's the first substantive evidence of progress since Brexit. The knock-on effect of the deal will aid the UK's longer-term economic plans and is strategically important to reduce China's influence in the region. Britain's businesses will now be able to seize the benefits of trade from the other side of the world while continuing to push against authoritarian regimes as well as focusing on a trade deal with the US.
While hardcore Brexiters would like to pretend that the deal is a significant payoff for the decision to leave the EU, the agreement holds no real economic benefit. A trade deal so contentious that it united Donald Trump, Hillary Clinton, and Bernie Sanders in US opposition to its entrance, it only offers a 0.08% GDP increase, which is meaningless to the UK's future. No matter how this is portrayed, it isn't the reality of taking back control that Brexit promised.
There's a 50% chance that the UK will apply to rejoin the EU by September 2048, according to the Metaculus prediction community.