Yeh, that looks pretty cool. Whether or not the ability to design complex curves will actually help you EQ a track is another matter.
Spline-based curves are essential if you're an architect or mechanical engineer, but when it comes to audio filters the shape of the curve is almost irrelevant. Often, an equalization curve ends up being some really goofy looking asymmetrical graph with seemingly haphazard dips and peaks - it's always a surprise to see what the curve looks like at the end of the process. It would be awkward, I think, to approach EQ from the opposite direction, making assumptions about what the curve's shape should look like.
Then there's the unusual spectral display. I guess it looks kind of like a sonogram, which can be useful sometimes. I use Adobe Audition's spectral editor, which has a similar type of display. Whether or not it's "more intuitive than your usual logarithmic display", I guess only using it for awhile could determine that. My own intuition says that it's not going to be all that intuitive. (My favorite spectral visualization is Ozone's "critical band" presentation, which actually attempts to correlate measurements to human perception.)
OTOH, it is only $19.