Too bad, I would have preferred to defend your PC against viruses even when it is offline, perhaps by storing the signatures locally and then run in the cloud when online. So the PC is not completely safe if off line.
So I do not know to what extent it is more effective than other free antivirus that also work in the cloud, such as Bitdefender Free.
Tha sandbox by default places every unknow file into a containment environment, so you are safe from a virus unless the virus has a digital signature from a trusted vendor.
Of course, since this is Comodo Cloud Anti-virus, it’s supposed to catch viruses too, not only to contain unknown files… otherwise Comodo would have released a Comodo standalone sandbox.
But in order for CCAV to catch a virus, you must be online.
About web filtering, I think CCAV doesn’t have it right now.
My personal choise is to use an adblock (I use ublock origin) and enable the filters for malware domains