When you exercise, are you burning calories? Yes.
Are you literally burning calories, as through combustion the way most people understand it? No.
I guess a way to look at this would be akin to community trash fires that are sub-combustion temperature. Yay, now we don't have to truck it 100km to the incinerator, we can just burn it in the village square.
Composting is really challenging because a number of waste products, from citrus to inorganic or hybrid-inorganic garbage, can ruin the compost process and compost product. If someone leaves a metal nail in the compost pile and someone else later plants potatoes in it, that nail could end up in your mouth after a potato grows around it.
https://www.gardeningknowhow.com/composting/ingredients/citr...
That's insane. And by the same process, does plastic/microplastic in compost/soil, end up in fruits/veggies?
When it comes to organic waste it's basically always going to convert to carbon gases, unless you're burying it in a peat bog or something of that nature. At least here the conversion is in a controlled manner that theoretically allows capture, as well as being conversion into carbon dioxide instead of carbon monoxide, methane, nitrous oxide, and various other gases that have sundry externalities, including greenhouse effects.
Additionally, those microbes can often be used directly as chemical factories (or at least a bunch of scientists are working on this, with some production plants already in use). So the waste isn't being converted to carbon dioxide, it's being converted to inputs directly used for manufacturing. While this particular product isn't doing this, it might be adaptable for the purposes at some point.