We are in a beta service period and during this time, it's greatly welcomed to share your live feedback with AQoom!
Bitcoin Core is the full Bitcoin client and therefore takes up a lot of space as it downloads the full blockchain. Although the client is not rich in features, it does provide a high level of security as the private keys will be created and reside on your computer.
Bitcoin Core initial synchronization will take time and download a lot of data.
This is a semi-cold wallet and doesn't have any mobile capability to tap and pay on the go.