I have taped corners of paneling where they met regular drywall and it worked fine. We then painted. This was a basement spare room. I didn't tape the edges as this was just a spare room but now I think I should have to get a cleaner look. I left the grooves in place - they don't look bad when painted.
A couple of things to note:
-Make sure the surface is clean. I think a good cleaning, let dry, and then sand lightly to slightly buff the surface would insure good primer and compound adhesion.
-Make sure you have a nice level surface with edges securely fastened down near your joints. You might want to add some nails set below the surface near the edges to insure this before taping. A "springy" surface will not allow you to tape properly.
The vertical ridges could easily be filled. To fill them you will need multiple coats since the compound will shrink. I see the author only seemed to use one coat. Yes, only one coat will show shrinkage. You will need about 4, yes 4 coats with all-purpose mud. That's how many coats needed to complete screw depressions anyway. Filling this way is a lot easier than taping and there is no need for preventing cracks, as tape normally serves the purpose for.
To tape the edges and corners, use a regular taping technique as shown at
Taping Drywall Step by Step Instructions - How To Tape Drywall