For sitting? Recommendations are for desks no higher than 760mm (30"), over which the average height person risks injury.
When pointing out the shortcomings of a product, you have the average user in mind: the DK-04 is too tall to be comfortable for the average user (as in, in this case, a user of average height) to use sitting down, hence my pointing that issue out. (A bizarre issue, 'cos would it really have killed 'em to make it drop down to 760mm or less instead of 780mm? My sitting-standing desk adjusts from 700mm to 1,200mm and it was only cheap from Ikea.) If you're a giant, the DK-04 will be fine as a sitting-standing desk; if you're a midget, none of 'em will be any good for either use. As outliers, neither use-case was included in the article. (I'm 6', if you were still wondering, but only if I stop slouching; if I don't stand up straight, I'm 5'11".)
I'm not sure where you're getting that 780mm height from - the official site says it adjusts from 675mm-1160mm.
Then Lian Li made a mistake and/or has changed the design, 'cos when I wrote the article it said 780mm. In fact, here are the specs from its original press release: (My emphasis.) If it drops down to 675mm, that's a lot more useful.
Someone in the PR department screwed up, because this is what Lian Li's Website says... I also notice that the website says it will take eATX motherboards, but that is omitted in the press release.