Generally speaking, its hype. It depends on the particular tanto and particular clip point we're talking about. There are clip points with huge thick tips, and tantos with sharp pointy tips. But generally speaking, consider this:
Clip points tend to come to a very sharp point. The tip starts to thin fairly far back on the blade.
The Americanized tanto (ala Cold Steel) keeps its full thickness to very near the tip, then switches to a full flat grind.
So, which do you think will penetrate better? A needle-tipped clip point, or a thick-pointed tanto point with lots of metal behind it? In this scenario, the clip point will penetrate easier than the tanto, but the tanto will have a stronger point. More metal behind the edge means worse penetration but more strength, generally speaking.
Unfortunately, you can't really talk in generalities. There are tanto formats that are designed to pierce really well -- but those tantos won't have the strength advantages of thicker-tipped tantos. And, on the contrary, I have a knife that's close to a clip-point blade, but has a similar grind to the tanto, leaving very much metal up front; its point is very strong, but its penetration stinks.
I just reread that old thread -- I had forgotten how long ago that was. I see some things I wrote then that I now know are wrong -- it's not difficult to penetrate the thin sheet metal auto bodies are made of, and even folders can penetrate pine without breaking. I still think an American tanto will penetrate better than other profile blades with the same width and thickness, though, and I still think that isn't enough to make up for the disadvantages of the American tanto design.
I've got a knife around here somewhere with an American tanto blade only 3/8" (9.5mm) wide and 1/8" (3.175mm) thick. It penetrates -- but so would other profiles with that width and thickness -- in fact, with that width and thickness even a sheepsfoot profile would penetrate pretty well, though not in a straight line.
I've done more experimenting on pine since that old thread and now I think if the spine is straight there isn't a significant difference in penetration between an American tanto profile to the edge and a curved edge.
The profile of the spine is much more important than the profile of the edge in penetration, so much so that you might as well ignore the profile of the edge.