I hear that most of the wear of an engine is on start up as oil drains from top to reservoir and lubrication is important. Also with all these start stops you will have to beef up the starter so it does not wear faster. I also hear on new cars with this feature you can turn it off and probably depending on car it can remain set or you have to do it every time you drive.
IMHO the biggest offenders of idling are government workers. We have all seen police sitting around in their cars for lengthy periods with the engine running. With today's electronics the excuse of needing to run the engine for them is probably not true.
Once walking in the park I came across a project were there were 6 county vehicles, one with an operator and the other five idling with guys standing around. When I told one that they were wasting gas the guy told me, yeah and you are paying for it - really.