Originally Posted by BigFlyer

I recently flew from Toronto to the US and pre-cleared US Customs and Immigration in Toronto.

As far as I can tell, from the perspective of the passenger, it is an inferior system to clearing in the US as in arrivals from other countries. You have to get to the airport sufficiently early to allow for the unknown total time to clear security and customs/immigration.

When one comes from a country where there is no preclearance on flights to the US, you allow for security (and outbound passport control if there is any), then, when you arrive in the US, you go through customs/immigration and it takes as long as it takes, but you are not adding on the additional time you need to add on so as to be sure to not miss your flight in a preclearance situation.

Am I missing something here, or is there some way it benefits the passenger? If not, is it benefiting the airline or the US government in some way?