The approach is different but in both cases your bike is monitored by default.
You can find more details in the documentation provided in your box and on the website.
In “Standard” mode you don’t have to do anything. Your bike is always drawn and you find the position points in the history. You receive alerts during a movement. You are free to cut notifications. This mode is very simple. The big difference with the “Expert” mode is that in “Standard” mode you always have the track of your bike, and you will receive notifications even when you use your own bike. If you leave the notifications, when you leave by bike, your phone will beep and a notification will appear on your phone, you will have to answer it otherwise it will beep again 1 minute later. The tracker does its job. You can cut notifications before leaving or once gone with one click.
In “Expert” mode, the energy-saving tracker uses your Bluetooth to find out if the person using the bike is registered as a trusted person. It will not send a notification when you use your bike. It will be on standby and you will not have the track either. Carefully a tracker is useful for theft, use a GPS type Garmin or your phone if you want to have the track of your route. The two functions should not be confused. The goal of a GPS tracker is to be on standby as much as possible to save energy and to be sure that the person who makes it move is a trusted person.
The “Expert” mode is intended for people who ride with Bluetooth enabled and who have a simple use: home/work trips, road training. If, for example, you are going downhill, and the bike is put on the lifts, out of reach of the Bluetooth, then keep the mode “Standard” with notifications cut because in “Expert” mode you will be notified permanently. Same goes for a bike messenger.