Depends on where you are in the "feature chain".
The people putting together (and packaging, shipping) the surveillance and Alarm monitoring systems factory benefit by getting paid for their work... along with the sales people, marketing, designers, accounting people, the building owner where all these people work and all the other folks who work for the manufacturer.
The retailer sells the equipment, so they benefit, too.
The person purchasing the equipment benefits because these types of systems can provide piece of mind when installed/used properly - and may even provide the benefit from reduced insurance rates.
The person who did the installation (assuming they are a contractor doing the installation) benefits because they get paid for doing that work.
These devices use electricity, so if these items are correctly installed, the company providing the battery back-up and the company providing the power to keep the battery back-up systems charged get paid.
Then, the people who commute in their vehicles or whatever transportation method they use purchase fuel (personal cars) or tickets (public transportation), (buy electricity (electric cars), live in houses they own or rent/lease and the money paid for all that benefits whomever receives the payment for these benefits. And all these people buy food, clothing, snacks... and they may have health and dental insurance which they fund along with their employer... And their paychecks (hopefully, at least part of them) get into a bank and the Bank folks can invest that money to make more money... the chain is fairly endless.
Is there something in particular you were looking for?