I think the security level is different. I wouldn't use a shredding service to dispose of old checks or my social security card, but for things that don't matter to the real world like performance reviews or meeting notes, I think it's fine.

Everywhere I've worked, the bin has always been "secured" with a three-pin lock that can be picked with a paperclip. That's a good way of expressing how seriously document destruction is taken.

I know at an ex-employer of mine, we chose to use an outsourced shredding company mostly because of legal reasons. I'm not entirely sure how it worked, but since we were handling PHI (patient health information), we had certain rules we had to abide by, and were liable if this data got out. Apparently, the outsourced shredding company insured us against some of these liabilities. I imagine police departments have similar situations.