Don't know if I can agree with him driving it on routine trips around town. Not only because of the extra gas consumption and CO2, but it also takes up a lot more room on the road, and it's a lot slower on acceleration wasting everyone's time behind him. When someone has a purpose for having a huge truck on the road you tolerate it, but if I found out I was stuck behind a slow firetruck because some guy wanted to tickle his own fancy I'd be less tolerant.
Yea, practicality isn't the end all of life, but don't be a dick.
Edit: Just wanted to add, it also puts a lot more wear on the roads especially during spring when the ground frost is melting. You might be within the law to drive it around, but your County Road Commission will not be pleased.