Mycellium wallet was designed by a team of some hardware engineers that later adopted Bitcoin at inception and decided to build a wallet for storing, sending and receiving it which they launched in 2014.
It was first created for Android and later for iOS. The wallet is one of the foremost Bitcoin wallets and it has maintained a stable status since then.
The wallet allows easy backup of private keys for security purposes. It also provides address book for keeping bitcoin addresses to facilitate and quicken future transactions.
In term of ease of use and convenience, it allow user to manipulate phone camera and scan QR code in other to initiate transaction.
Another advantage is that user has the option of choosing from available transaction fee options which will also influence the transaction speed. It is also an HD wallet.
Older wallets like this are preferable to newer ones because of their record of stability.