Students don't have any disciplinary authority over other students, nor any ability to immediately intervene when appropriate, which paraprofessionals and SROs

Students don't have any disciplinary authority over other students, nor any ability to immediately intervene when appropriate, which paraprofessionals and SROs do. And SROs absolutely do escalate to the criminal justice system (e.g. juvenile detention) when necessary. There are occasionally guns, knives, drugs, and violence in schools, and those are situations where the legal system is frequently involved. The bottom line is that a student hall monitor is going to be able to snitch on an otherwise good kid who is goofing off in the hall, but they're not going to be able to deal with more serious issues. And it would be a very bad idea to rely on them as the front-line workers for more serious issues.