What is the benefit of activate Check in/out?

It is one of the important premium features, with Check-in you can show that there is already a participant in that meeting arrived to the room and it is important that it will show that the meeting will already going to happen
For Check-out also is excellent feature to save more time so for example if the meeting finished before its time, the time can be used in another event so that way you can save the wasted time.