Why would a voting share in a firm without dividends or with no assets be worth anything? Voting just gives you input into a future course which will hopefully give the firm assets (from which it may or may not issue dividends), but the voting shareholders will presumably pursue that anyway, and if you don't have better ideas than they do on how to do that, your vote isn't actually netting you any additional value.
All stock is based on the (possibly expected future) value of a share of the net assets of the company. There is nothing else that could provide it value. Voting rights are just a way to have input on how the company will try to realize value and how and when it will distribute it to those entitled to it.
The benefit for shareholders is that the shareholder can decide when to recognize that as a capital gain; the negative for shareholders is that they can't recognize only the portion of their capital gains related to the buy back.
And indeed, non-voting shares in a company that doesn't pay dividends seem worthless to me. And who decides whether the company pays dividends? Not the non-voting shares.
Non-voting shares could be fine, but they could also turn out to be a scam, depending on the wishes of the people who control the company.
I'd say the opposite is true. It's more likely non-voting share prices will crash because it's now clear to the market that voting rights are worth quite a lot given that they can be used to steal money from non-voting shares.
If not, what is the value of a non-voting share? Particularly for a company that doesn't pay dividends and doesn't have substantial material assets to sell in the event of liquidation (my impression is that this describes many or even most modern publicly traded companies)?