I'll admit, I'm not familiar with Inktense Wood. From what I can gather, your question is along the lines of 'Do I need Inktense Wood to create a realistic wood surface?' And my intuition would suggest... no.
I gather this is the effect you're wanting (Just a random image from the net, not mine):
The artist here has acheived the effect because they've created some interest on the surface by mimicing the wood grain with striations. The Inktense Wood simply tints it brown. So it follows that if you already have a brown ink that you like and it's the shade you're looking for - then you don't need
IW. You can acheive the same effect by picking out the wood texture with highlights, then slapping on a wash or ink of choice. Bear in mind that washes and inks work differently. Washes pool in crevices, and provide greater contrast/shading. Inks sit evenly across the whole surface and tint the base colour to create a different hue.
So no - you don't have to use
IW at all. It's the technique more than the colour which creates the realism. I'd guess the positive reviews for
IW in particular is that it has a nice rich brown colour which is neither too red/orange, nor too tan/yellow (Funnily enough, this is actually difficult to find in household wood stains too - lots of red 'teaks/oaks', not too many brown 'mahoganies/walnuts').