I have both a security system and cameras (which are on my phone and at times monitors at the house). It wasn't cheap but there is no way i would do it any other way now.
I started with 4 in 2019 with a local recorder focused on my IBA,
Changers and Paystation. 2 years ago i went site wide, 2 per bay, multiples covering the parking lot out front with the vacs and out back and the pump room. I have motion detection zones on the cameras activated through the night that notifies me via text and email if somebody is on site. If they look sketchy either i can come out or make a phone call to the PD to do a drive through, my local pd loves coming buy. Since i have installed them they've come to me for video footage for several cases they have worked in the area and i have always come through with something to help them out so they kinda repay me the favor by helping keep an extra eye on the place.
To say the least i feel like they have more than paid for themselves, not only by helping catch the people we don't necessarily want as "customers," but it has dramatically helped with troubleshooting and preventing various issues that have arose since that time. Its not fun to look on the camera at 11pm and see water in the floor of the pump room but i caught it within 30 minutes of the line breaking instead of it flowing until i got here the next morning at 8am.
I honestly don't know how we did it before the cameras were installed, but my life is so much simpler now.