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.