While I do trust Coins.ph in terms of security and what nots (I also have some BTC stored in Coins.ph for easy withdrawal to fiat), it is worth to note that there is no 100% secure way to store anything online.
The most likely scenario that could happen is for an exchange or wallet to disable transactions for a cryptocurrency. Even major exchanges like Binance and Poloniex had disabled Deposit/Withdrawal transactions before for crypto's like Steem, holding the users money hostage for days/weeks (and around 6 months for Poloniex).
While I don't see this happening for Bitcoin, it is still a likely possibility for small exchanges and local wallets especially now that the hype for Bitcoin and crypto is starting to fall down here in PH. So only store what you can afford to be stored for some time. XD
Storing bitcoins in any digital wallet is not risk-free,we have heard many situations whereby some digitial wallet where hacked and the bitcoins of so many individuals were stolen...you should store your bitcoins in a cold storage if you want more security for your cryptos and keeping it safer...
Where you dont controll your private keys, there is no safety.
The less risk is with a cold wallet, and the highest risk is in any online service, where you have just a "virtual balance", and the company handle your keys and your money.