I've understood it like this : Taiwan is a successful, politically stable liberal democracy. It's existence contradicts the CCP stance that democracy is inherently Western and inconsistent with Chinese culture. [* I have no citation for this, I feel I've read it multiple times ] The CCP stance delegitimises Taiwan and the example of Chinese democracy it represents. Military pressure adds to this, because it creates uncertainty that Taiwan will be able to maintain control over its territory in the future, and pushes Taiwan to need support from the US, which feeds the argument that it is not a true free standing Asian country, but an artefact of foreign incursion.
China is a big powerful country. But that shouldn't be surprising. I think you can argue that China has been the most important centre of human civilisation and scientific progress for most of human history.
I wonder whether the CCP are concerned that mainland Chinese would otherwise look across the Taiwan Strait, and rather than thank the CCP for the success of recent decades, would instead wonder how much better life might be if China was more like Taiwan.
That's the benefit. But what's the cost, and is the cost outweighed by the benefit?
Invading someone, particularly if you haven't practised, is expensive, difficult and prone to failure. And if you fail, you've shown impotence in public.
So maybe investing in your own high tech manufacturing is has a better chance of succeeding for the same level of effort, if you see what I mean.
And what is the plan for resolving the cultural/philosophical difference between East and West?
It seems to me that there must be some active resolution. And if we aren't careful it could default to warfare.