You don't give a size on the cage you posted nor the length/width of the spikes that are meant to hold it in a vertical position but at first glance, it appears that perhaps the cage is meant for installation before the plant/tomato/whatever is big enough for the roots to be an issue.
In my own caging experiences for tomatoes and the like, I've found that you can push or drive anything within reason into the soil without doing too much root damage AS LONG AS the soil has good tilth (basically defined as the tightness or looseness of the soil involved), you move slowly, and push the stakes down with your hand as far as they'll go before you take a hammer to them.
Although I tried commercial tomato cages for a while with little luck (usually too small or short for mature plants), I finally started making my own cages out of concrete reinforcing mesh (usually about 4' wide with 4" to 6" squares).
As to the product shown, I'd probably not purchase it for my own use as I've bought and tried too many "got to have it" type products over the years with little luck but that's just my opinion...
Steve in TX

It does look interesting. I would like to know what the product is made of: metal or plastic. And, what is the material that spans from one upright to the next?

I agree with Steve about installing the device, about being careful. My tomato roots don't spread out too far and they are tough and could withstand those pointy things - I think.

What really puzzles me is the timing of this. I don't believe that this is the right time of year to begin testing new products for the garden. Unless you are in a location that the heat of summer has passed and only now can you begin your vegetable garden.

This device might also work on cucumbers or other 'clingy' veggies.

Jim

Yeah I think I will just put the cage in before planting. I was thinking about getting the soil wet and then carefully placing it in. It looks like the spikes are about 6 1/2 inches long and 1 inch at the thickest.

The cage is made out of recycled plastic. The trellis around the cage is a soft tie. It is an added feature from what I understand.

They sent me some clips too. Ultimate Plant Clips? Anyone heard of or used these? I'm excited about them, I have put them all around my garden - on my berries and other misc places. Super easy to use.

It doesn't look sturdy enough for tomatoes or most edible vines to me. Maybe Dahlias. If it costs more than the standard wire tomato cage, I wouldn't spend extra on it. Agree that plants expected to require staking should be staked before they need it.

"They say I can put it around an existing plant..." That's the kind of claim marketing people make, not gardeners who wouldn't be in that situation anyway. There isn't really a need for that, but I agree that slicing a few roots is not something that would bother most plants, so installing a stake late would be fine. The spike things at the bottom of the stake pictured look like they would slice much more roots than a traditional wire tomato hoop, so it seems like a strange claim to make unnecessarily.