For us to create your Ethereum wallet, we need to initiate a smart contract, and this operation costs a small amount of ETH.
Simply put, a "smart contract" is a way of getting things done on the Ethereum network. The best way to describe how it works is to compare it to vending machine. In order to enjoy the goods and services on the Ethereum network, you need to drop Ether into the vending machine, and it will provide the goods or services you requested.
The 20 PHP fee for creating your Ethereum wallet is passed on to the Ethereum network. Coins.ph will not profit from these fees.