Bluetooth® Smart uses the frequency range of 2,4 GHz. Giving a frequency range is much wider (2400 MHz up to 2483,5 MHz) than with 433MHz accessories, therefore there are fewer risks of interference with other accessories, unlike a 433 MHz that is very widespread.
A device using Bluetooth® Smart can send information on every change of state to remote control its situation. Thus, if your door is open, you can be aware of it. Whereas a 433 MHz device only sends/receives raw information without any feedback. You can never know if your plug is on or off or if your electric shutter is up or down.
A 433 MHz accessory requires a manual learning for each of its possible actions, unlike Bluetooth® Smart. The recorded sequence needs to be reproduced as it is, it is then necessary to press only once on the corresponding button.