On the scale that Climeworks is operating at? Probably not really. You can read that "downside" more generally as DAC (and carbon sequestration in general) is

On the scale that Climeworks is operating at? Probably not really. You can read that "downside" more generally as DAC (and carbon sequestration in general) is expensive, and no one really knows how efficiently we can do it, especially at the scales we'd probably want. It's also an expression that current low/no carbon energy sources are globally sufficiently constrained that we're in no real position for large scale (aka meaningful) DAC (and many other forms of carbon sequestration - perhaps not all) deployment. Climeworks is clearly out to iterate and gain experience to be well positioned for a presumed DAC (and sequestration) market that may form as all of the easy to decarbonize sources and processes are converted. We're... a ways off here.