...just something the airport puts up for info of the public
Let me give an example of how it misleads the public. I recently went (by car) to GLA to collect my daughter. Now parking at most airports can involve a significant walk to the terminal. My daughter is handicapped and cannot walk far and has to be accompanied by a carer. So I used the much closer dedicated drop off/pick up point but where however you cannot simply wait indefinitely. So it was important that I should arrive at the pick up point at the appropriate time. Had I simply taken the estimated time as being the gate time, I might have arrived too early and would have had to enter a “holding pattern” in my car. So times that are estimated landing times and not estimated gate times can mislead for Joe Public who doesn’t necessarily understand the difference. At GLA, the difference is trivial - only a matter of a few minutes - but at somewhere like AMS it is significant.
And of course, for some car parking, you have pay and display and have to guess how long you will need.
Confusion reigns as already noted by another contributor to this thread.