There are some countries that recognise Taiwan (Republic of China) as the sole legitimate government of China instead of the People's Republic of China.
Recently, just a few days ago, São Tomé and Príncipe switched its recognition from the ROC to the PRC.
According to Wikipedia, there are still 21 entities that has full diplomatic relations with Taiwan:
So, why do they recognise the ROC and are there any benefits for doing so?
Note: Sources or examples are greatly appreciated