The first is that you're going to have investment banks declaring their employees cars as commercial.
The second is that you don't have to be a business to take a job taking care of a planter (or whatever). You probably are, but it's not required.
I agree with the principal that "nobody needs to commute in a personal vehicle", but I find it hard to codify it into a reliable law.
Edit: Actually I like Nihonde's own modification: “small trucks/vans on demonstrable business”, I'd add "involving transporting stuff for use in the city".
It will probably still be gamed, but the ambiguity of the wording allows selective enforcement to fight the worst of that.
Edit 2: Actually I don't, considering the other discussions in this thread about police abusing their authority giving them more ambiguous laws seems like a bad idea.
Also - This is a perfect example of why I try to avoid advocating for/against policies on the internet unless it's abundantly clear that they are good/bad.
If you really need to drive around in lower Manhattan once in a while (e.g. you are doing a big run to Home Depot), you pay the $5 fee. Unless you are truly destitute, it's not that bad to pay a couple times a year.
The price system isn't perfect, but it's pretty damn efficient at controlling quantity demanded.
EDIT: I'm not saying wheelchair-bound and other similar people should be banned from driving. Like today, we can add wheelchair-only parking accommodations. In fact, restricting traffic to only people with a genuine need will make their trips faster.
Besides, even if you are on a wheelchair with lower body paralysis you can still drive with hand controls.