Why tax those other things? Is there a moral reason to do so?
I'd say there's a moral reason not to!
Is there a practical reason to tax those things? Not if the goal is to maximize government revenue!
If you tax land as high as possible -- at 100% of rent -- then it's not usually possible to increase revenues by taxing the stuff you mentioned. Doing so would almost invariably decrease the revenue the LVT raises by more than the revenue your proposed taxes would raise.
There are exceptions.
1) Certain non-traditional land like radio spectrum, minerals, pollution rights, parking, space on a congested highway, etc can and should be taxed.
2) Some luxury goods could be taxed. Whether or not they should probably depends on the situation and opinion. (By luxury goods, I mean goods that are valuable in part because other people don't have them. A cell phone is thus not a luxury good, for example, because the more people have cell phones the more useful your phone is. Luxury goods in the sense I mean are not merely "expensive" or "for rich people," though most luxury goods are.)
See ATCOR: http://www.wealthandwant.com/themes/ATCOR.html