Welcome and enjoy the new ride.
As the owner of MB cars for the past 12 years, I found they are on the safe side in their design. MB does not want anyone to get hurt and then have a law case to deal with. Therefore must depress the button and hold, as Wayne said.The "hold to adjust memory seat" is considered a safety issue for MB. If you hit the wrong button and got scrunched into the dashboard, that would be considered bad by most.