The land-only component of Taiwan has value, but not worth invading for.
China desires the economy of Taiwan, the people, and retribution. All can be nullified via the “nuclear” option.
Many people have fled Hong Kong, especially because the UK welcomed them with open arms.
Taiwan can choose this, if they want, as a response to an invasion from China:
- Everyone leaves for foreign lands who have promised to look after them
- Infrastructure is destroyed enough for repair costs to be not worth doing
- All non-Chinese business relationships vow to not do business with a Chinese run Taiwan
I don’t think this tactic has been tried before, but presumably it would scare off China.