I think it falls into a different category than having a compressor, the compressor isn't portable in the same way, you'll end up taking whatever it is to the compressor rather than the other way around.
They both have a place i think in the same way a pillar drill drills holes just like a battery drill, they're just for different types of jobs.
Exactly. If you fancy lugging around a compressor every time you need a quick squirt then have at it, I'd rather just pull this out the drawer, blast and done.