Alright, let me get started.
First, you're right - our CURRENT hover tech relies on conducting materials to do it. It doesn't mean it's never going to transition elsewhere - in theory, the technology in the Hendo board could be developed to work on any surface with a magnetic field strong enough (containment is another issue, of course). But the amazing thing about technology is that it always evolves - we might figure out more ways to do it in the future.
As for the upsides - there are plenty. Physical, or kinetic, friction is one of the strongest, if not the strongest type of friction. By removing physical contact, we can increase efficiency of most mobile technologies in theory - faster and more fuel-efficient cars, quicker and more silent conveyors and forklifts, and hell - with that technology, I can easily foresee magnetic tethers that astronauts could drag across the ISS' surface to access everything without risk of drifting or tangling up. And since it uses neither supercooling nor superconductors, we could also build a more flexible rail system for many things, from rockets to warehouse cranes.
And another advantage is that hover technology, in theory, has very little to no moving parts. Which means no mechanical wear, which also drastically increases durability and reliability of things.
And as the Kendo article, if you read it, claimed - this technology will also be very useful for places like California or Japan who get a lot of earthquakes - because non-physical dampers are often more effective, and give a bigger buffer before things start to go wrong - current solutions can bend and break. This technology would have to hit the wall hard to fail.
As for traction, you're entirely right - there's literally no traction, because that's not what hover tech is for. We already have hovercraft that uses air cushions - and they are entirely driven by aerodynamics. This tech won't entirely replace wheels. This tech, however, WILL replace caster wheels, conveyors and such things.
And of course, there's the military applications - properly designed pods could be used to make a missile not unlike Ironman's Jericho missile. Transporting large amounts of cargo will also get easier. And the kicker? Saltwater IS a conductive surface - which means that watercraft, in general, have the potential to also get improved in efficiency and speed by this technology - better coastguard, better battlecruisers, better tankers. There's also the possibility of making, with these, a gauss cannon - the military already uses, in a lot of cases, copper bullets (often with steel piercers). Which is a material already compatible with the Hendo technology.
So in short: yes, hover technology is worth investing into - it doesn't look like it because it's an early technology, but history says that the technologies with the most skeptics are most often going to become staples of our civilization. Like internal combustion engines, airplanes and nuclear technology.