Yep, typically I am not hauling passengers on that server. Thanks
If for example you use one of those tickets on the city screen (passengers section), it will add 2 more hours to the time, waiting time is reduced ... for all.
So it might be wise sometimes to use that voucher on a neighbour city, where your mates are getting passengers to haul into your city.
But most important: if you haul passengers or not ... when the city levels up, you will get prestige points for having spent that voucher.