A lot of programme editors have an odd aversion to Double Boxes, I think their reason is that they've spent all this money on some lovely 103" flatscreen monitors, why use a DVE when they could see the contributor in screen?
Usual argument is that there is no 'relationship' between the studio interviewer and the guest (though how much relationship can you have with a TV screen?) - and it's cold, distancing and 'newsy'.
I think probably a reaction to the 80s and early 90s when they were everywhere and large screens were poor quality and expensive, so it was a choice of DVE boxes, small CRT direct-view, or larger Mitsubishi/Barco CRT projectors (which were often a bit dim and murky)
In those days, before plasmas, affordable bright projectors etc. DVE boxes were often the least worst solution. (Though they did require a dual channel DVE - or some Heath Robinson box wipes and off-set framing, or cameras pointed at floor monitors...)
Once plasmas etc. arrived in the mid-to-late 90s, along with affordable projectors with decent performance, in-vision screens became dominant. ITN even simulate them in their virtual set.