Namely you need to look at the total cost of manufacture, especially with respect to the environment and/or CO₂ impacts.
This process, excluding inputs, has a lower CO₂ impact than traditional concrete. It also, currently at least, produces a less useful concrete, as it isn't as strong.
The question is what is the net environmental and CO₂ impact when you also include the inputs.
One area where this new process has a positive impact: * No need for virgin river sand, although it is unclear if desert sand could be used. At least this would be a good way to "recycle" concrete, which is notoriously hard to re-use.
One area where it has a negative impact: * This concrete is no longer vegan friendly. Although to be fair, many plantation woods are not strictly vegan either, since may plantations directly lead to a lowering of biodiversity and/or loss of animal habitat. Sand mining is also typically not "victimless". * Requires a more diverse input/supply chain. Although the article doesn't really go into the impacts of this, so it's hard to estimate how bad this is. For example, do we need a kg of gelatine per kg of concrete, or per tonne of concrete?