Any advantages to bi-wiring speakers vs. single

If you get the bi-wire version you will have more flexibility down the road should you choose to go down that path, or to bi-amp also. No downside that I can see.

No whether bi-wiring makes a difference on this particular speaker ... that I don't know, but I'm sure you will get your share of people taking both side of that question. :)

My speakers are set up for bi-wire. May be more "lore than law" but per the manufacturer, bi-wire sounds better than straight wire. Who knows??? Could be hype. But as Ptm... said, also permit bi-amping as well. Most people seem to agree that properly set up bi-amping does improve the sound.

I have VonSchweikert VR4JRs and they sound MUCH better biwired than single wired. I spoke with Albert's son at RMAF and he recommended the biwire option which is about $200. extra. I'd do it if it were me.
As ptmconsulting suggests it does ope up several options for the future; you might want to ask VSA if bi-amping is an option with the bi-wire upgrade.

Biwreing may or maynot benefit since you're adding a reactance to crossover equation.
Biamping is what biwire terminals are for to benefit.

If you are not going to biamp then it is just a hassle to have biwire imho. Need biwire cables and some agrue you need true biwire cables or double runs for best sound. Others say jumpers are better and then you have to choose which jumpers sound best...

Opens up a lot of possible directions and results. Some like this others feel it is a hassle. If you like to tweak and mess with gear, then biwire is good. If not, then better without it.