This allows opportunity for expansion, but need higher power output, transceivers are larger. The power requirements is bad for hand held devices. Bluetooth is some way away from having an integrated network. CDPD was rolled out with big charges which hurt deployment. Bluetooth is more at a nacsent engineering stage.
Security is a concern.
There is 128bit encryption cards which cost extra. The DFSS is impossible to pick out of air and is very secure. However, if everyone is using the same DFSS compatible radio equipment, then the DFSS does not work for security. So add encryption. But each physical client has to be equipped with a key which will be the same in every host so info will get out when have hundreds of people.