The exercises right in front and sometimes inside Taiwan's "territorial" waters are highly significant for China if it manages to normalise them. Basically Pelosi came, (excuse my words) took a dump on China's face and left, that's it.
But what about China you ask? Well, after this brief touch and go from Pelosi, now China will forever do exercises even inside Taiwan's "territorial" waters! This is very important.
Apart from the operational military benefits, China now will also be able to easily suffocate Taiwan's lines of communication at a moment's notice. During a normalised "exercise" it can suddenly start using amphibious forces to land to Taiwan very quickly. It can cut lines of communications for ports, naval supplies etc. It can also use pressure tactics to drive Taiwan crazy with constant annoying military exercises, or even provoke Taiwanese forces to fire the first shot etc.
Even more, it can now "punish" Taiwan whenever a delegation visits Taiwan. More exercises, getting more of Taiwan's teritorial waters, more aggressive training profiles, become more disruptive to the local economy etc.
We can conclude that China will now get another vector for pressuring Taiwan, the sea. If before China was only using the ADIZ incursions to pressure Taiwan, now it will also do from the sea with violating "its" waters.
So overall, I consider Pelosi's visit to Taiwan as huge PR soft power win for the US (and a PR disaster for China). The US can now use this meeting as a "kicking-the-door" and allow its puppets to send their own delegations
On the other hand, China gets (assuming the exercises get normalised) a huge strategic win for hard power. I really wouldn't like this trade if I was Biden right now(does he even remember that China is a country?)
This broadly follows the current trajectory of the US and China. The US tends to focus more on soft power benefits and China is the opposite, it is laser-focused on gaining hard-power.
The only big question remaining now is:
Will China normalise these military exercises. If yes, then for China, this debacle of Pelosi's visit was more than worth the trouble, its a big win for China. If no, well, its a big loss, take the L, go home and lick your wounds for another 5 years before coming back again