Any mobile phone with advanced features like bluetooth, infrared and a USB port has other uses apart from making and receiving calls. The other uses of mobile phones that people are familiar with are using them to browse the internet, using bluetooth to transfer files such pictures, music from one phone to the other (that is for bluetooth enabled phones).
But these mobile phones have more uses which most people are not aware of. One of such is that these mobile phones can serve as storage devices of important files like pdf files, microsoft word, powerpoint and so on. Yes, any mobile phone with the bluetooth technology or USB port can play the role of a flash. The storage capacity of such a device is increased if it has a memory card or a slot for a memory card. So you see a mobile phone with advanced features is a good computer accessory.
Again a mobile device with bluetooth or USB port which also have internet connections can be used as a modem attached to a computer. This feature is useful for people who prefer private internet network services provided by telecom services. So you see your advanced mobile phone is an important computer accessory.