If you're using this as an alternative to spray-bottle canned air, it will never ever be the cheaper option. Ten lifetimes could go by and you wouldn't pay for an electric air compressor with the savings from canned air.

I don't think that's fair. Decent canned air is what, $5 per can? A quiet compressor is under $200. If you're doing any hobby work that requires frequent use of canned air, it can pay off in a year. If you use it very infrequently, then sure.

Air compressors are easy to find and operate, and they do make reusable compressed air sprayers that you fill up with a compressor.

Why? The compressor already has a tank, you can just use that with an appropriate nozzle.