Myetherwallet is an ERC20 base wallet which means it support all ethereum base token multiple token are supported by this wallet which makes a user to store multiple coins in one wallet.
Being a blockchain base wallet daily coin rates according to their increase in price are displayed on the wallet, with this wallet a user can create and open multiple account in as much as a user keeps all his private phrase key secure in a safe place because every user has full responsibility over his wallet account and details.
Myetherwallet is not just a mare wallet, it's an interactive base wallet that actually all it users to create multiple wallet of their choice since those users are in charge of their security and passphrase.
In term of security myetherwallet being a blockchain network there is no doubt that security of this network are highly guarded with secure server and good upgraded softwares.