The security is the network, what RIM/BB is known for.
One advantage is BBM uses a PIN, not email or your phone #. Keeps some privacy, similar to Kik.
If your unfamiliar with BBM, a Youtube search will show you all you need to know.
I am hoping the message delivery is more reliable than WhatsApp. Many people on all platforms have issues with this on WhatsApp.
BBM used to have a music aspect, but I think they abandoned it. It has Wifi voice and video calling, which is supposedly very clear (Only on BlackBerry platform, for now.). There is BBM Channels. I also like that BBM shows "S" sent, "D" delivered, "R" read vs WhatsApp check marks for sent and delivered. Pretty sure BBM has GIF support. It also have screen sharing via video chat. You can choose to send higher quality pictures on BBM, if desired.