I'm highly suspicious. The Voynich has attracted attention for decades, and like anything popular, sometimes it brings along people who have no idea what they're doing. Ars Technica was surprisingly credulous, and doesn't seemed to have paid much attention to Gibbs' actual methodology.
Or perhaps better said, lack thereof. He seems to have decided based on the pictures alone what he was looking at, and then come up with a theory for the text that matches it. He conflates "ligature" and "abbreviation," which aren't the same thing. An abbreviation is a shorter way of writing something, the way we say "USA" or "DC" rather than writing out the place names. A ligature, on the other hand, is a way of making two letters flow together for ease of writing. Computers still do this; just look at the way fi combines in some typefaces. But ligatures don't stand in for whole words -- even the ampersand (which is technically both, since it's a single character standing in for two ("et") or three ("and")) started out as simply a stylized way of writing "et."
The file name for the tiny image at the top of the Times story suggests that Gibbs is writing (or has written) a book on the subject, and I expect this is part of the publicity tour. Meanwhile, there's a strange kind of cyclical nature to conspiracy theories and scientific mysteries. In this case, Gibbs' explanation sounds remarkably like another one that was proposed in 1943.
The comments here go into a lot more detail about why Gibbs' theory is probably wrong. This one in particular is worth reading, as he points out why it's so easy to get pet theories on the subject:
The fundamental problem is that it’s easy to decipher the Voynich Mss — just look at all the people who have done it, in whole or in part.
He then goes on to explain a couple basic things that attempts at decipherment typically ignore.
At the end of the day, we don't have enough information to say for sure whether Gibbs' approach is correct or not, but we definitely can't say that it "has been deciphered."