I think it's a fantastic idea, even if it's a bit of a raw deal for everyone involved.

The consumers don't get to use the product if they miss or pause a payment (but can continue paying later), but now have a route to get it that is not as cheap as piracy but still much cheaper than buying it outright and most importantly way easier and more convenient than piracy. It's the iTunes Store model.

For Splice and Duda/Xfer, neither of them are making a whole ton of money off of these, but they are now going to get sales that they wouldn't have previously had access to - people who have been holding off on buying it, and people who have pirated it and want a non-buggy, updated version. In the end, Duda will probably have made more money than if he had only offered it as a complete purchase.

Now I'm just waiting for them to add Nexus or Omnisphere.

I think this is a spectacular option for producers who want to start out but don't have the money outright for a vst. Some of these are  the price of two week of food for me. As a business standpoint, it just me they've offered more access to people who would only have dreamed of buying, (or pirating this.) With this method, they'll have my money every month and anymore products they decide to sell with this method.

It makes sense, most producers these days are broke college kids. If I had the option when I started I would've done it in a heartbeat.

Great idea! The best part is that when you've paid as much as the full price, you'll get the full license. Many services offer monthly payments, but once you stop they are all gone.