I'm not diabetic but my wife is - has been for 15 years. She feels - and I tend to agree with her - that any machine that transmits it's readings - Wifi or Bluetooth - can potentially be monitored by any passing bod who happens to be in a wireless hotspot. As such it could easily be seen as a) if the results can only be downloaded once you will loose them to A.N Other, b) this coulld be seen as an invasion of your privacy and c) could be an entry point for an alectronic virus into the machine. You can be sure that if it is possible some hacker will do it.
With this in mind I am not a great lover of wireless connections - this from a computer ngineer with a laptop loaded with anti virus packages.
Whenever you wish to archive your readings - think cable!!
Can't be hacked anywhere as easily.