Lower productivity: a slower internet connection, or the abscence of it, reduces the productivity of workers, simply because many jobs in the modern economy are done through the internet.
Less GDP growth: this is related to the above point. If workers are less productive, the economy's GDP will grow less, or even not grow.
Poorer education: internet has become a very important tool in education. If many young people lack internet, they will become less educated.
Less people learn internet skils: simply because many filipinos do not have the opportunity to use the the internet in first place.
Slower technology adoption: the internet is at the forefront of techological change. If this service is of low quality in the Philippines, new technology will not be adopted in the country as quickly as in other countries.