Before i experience of pending transaction from coinbase but it fix in few weeks.. like other said it is still risky o stay our bitcoin for too long in that web wallet because they are just giving a free service which is why they are giving it for free service.. but any way you transacting a small amount so if you lose there it is not a big problem.. i refer to use electrum instead of you want for better safe place if you are holding large amount of bitcoin.
Online wallets are all risky since we dont posses the private keys and if the online wallet crashes then say goodbye totally on our bitcoins.Regarding on coinbase i could say that they are safe for transactions and they do charge free in every transfer you made unlike on blockchain and other web wallets.