Bi-wireing speakers

I recently contacted Vivid Audio and they are moving away from making biwire or biamping available.

According to these articles they’re going the opposite way. And so do others. 

https://hifipig.com/devialet-add-axd-tech-to-their-expert-pro-line-of-amplifiers/

http://designwsound.com/dwsblog/2018/10/devialet-axd/

I follow Vandersteen's suggestion....never had trouble. 

"What would be the advantage of running two sets of cables to the same terminal on a speaker. "

There are no advantages to running two pair of wires to a speaker terminal.  That configuration is electrically identical to running one pair of similar diameter wire to the terminal.   

It can vary depending on how the speaker is designed.  Seems like some manufacturers believe it provides a sonic benefit and design their speakers accordingly, while others just put high and low terminals on there because they feel they have to.  Then there are others that just don't feel biwiring is necessary and just provide one pair of terminals. 

To me, if the designer recommends biwiring it is certainly worth exploring.  IMO, at the very least you'll want to replace the crappy jumpers that usually come with the speakers and replace with good quality wire jumpers.  You have to weigh the cost of what it takes to biwire your speakers vs. the sonic benefit, as you might find you'll get a bigger overall boost in performance by investing that money elsewhere in your system. 

The last consideration is whether to go with a full shotgun biwire setup, where you have two separate cables going to each speaker.  This is where I actually found the largest benefit with MY speakers.  In addition to getting rid of the wretched jumper, you've now got twice the amount of cable going to you speakers, which decreases resistance that could provide further benefits -- again very much dependent on your system.  This option, however, can get very expensive depending on what cables you're using.  While I got enough benefit from this to find it a worthwhile improvement, I wouldn't have done it until I had my other components where I want them since the benefits were of a more subtle variety versus upgrading something like a preamp. 

One final tip.  Despite already running a shotgun loom of cables, a cable manufacturer recommended I add banana wire jumpers in addition to the dual cables (the cables had spade connectors so banana connectors were not being used).  I was, to say the least, skeptical, but I was shocked that these extra jumpers provided a meaningful improvement both in overall clarity and transparency along with tighter and more well-defined bass.  Not huge, but very noticeable to the point that I wouldn't think of using my speakers without them.  The good news is, in the scheme of audio, this is a relatively cheap tweak to try.  Anyway, I've blabbed too long here.  Hope this helped and best of luck.