Re: Purpose
Depends what satellites are being thrown up. There are lots of things in orbital space that we use that save money compared to alternatives.
Stereoscopic imaging of infrastructure is useful for condition monitoring in lieu of ground based foot patrols.. It is competitive on all-up cost with the alternatives like helicopter or fixed wing patrols, and often has much higher frequency, meaning more chance of spotting risks in timely manner. There are compelling police applications too e.g. image comparisons when searching an area for disrupted ground (perhaps to find where someone has been buried... Grim, but is a real application in live use).
Infra-red detailed ground observations cameras aren't quite there yet with resolution to throw up to orbit but the tech is coming. Next couple of years are mooted. Because Physics, that capability won't be flying on virgin Orbit. (IR cameras with high resolutions will be big machines).
On a single point basis satellite services are dumb, but where more than one buyer uses such a system it's not hard to find value in them. Communications capability is self explanatory.
The major problem for Virgin Orbit is that as their payload is limited, like the Pegasus launcher before it, it's commercial value is quite tricky to place. "low" cost but not capable enough either for where the real commercial applications are.