The truck doesn't move unless its got a trailer behind it usually. That's kinda what I'm thinking its just a service writer trying to make his quota.
In all reality, it is not something that would hurt anything if you had it done. The fact is, it is call preventative maintenance for a reason, as it is meant to be done before a problem arises. It is all in the presentation of the service writer on how well they explains that. Necessary? No. A bad idea? No. Are you going to have problems down the road that could be prevented with this? Maybe
If the service also helps to clean EGR, intake, ect... It would for sure be a good idea as most know how gunked up the system can get.
Just an opinion on the outside looking in.