It's better to store BTC on coinbase , it's fast and secured. Blockchain is down sometimes.
coinbase is good place to store your bitcoin, also he give 100% free fee transfer, so you can spend it every day without thnk about "fee"
and coinbase give option 2fa with sms verification, i think it's very safe
It is safe as much as you stay safe, use difficult password, coinbase it's for a long time in the market and i don;t think will bankrupt so it should considered as a safe web wallet.
https://www.coinbase.com/vault
~TIME DELAYED WITHDRAWALS
Withdrawals from your vault have a 48 hour window during which they can be canceled.
~MULTIPLE APPROVERS
Joint accounts can be used for extra security, requiring multiple approvers to initiate a withdrawal.
~OFFLINE STORAGE
98% of bitcoin is stored totally offline, in geographically distributed safe deposit boxes and physical vaults.
I have seen that option but never tried to use it, what do you meant time delayed withdrawals, i can make a withdraw and after 48 to get confirmed?