There's a pretty wide spectrum between: "Can't discipline kids that act up" and "Beating kids"
Kids need boundaries. It's literally what they spend a good portion of their time testing for. If you aren't allowed to provide boundaries for them, then they will flounder, which turns into a self-reinforcing cycle.
I've heard from some teacher acquaintances that it's highly discouraged because the parents tend to complain a lot and the kids view it as a free vacation from school.
It sounds like "try to ignore them" is basically the only recourse teachers have in some districts against disruptive or worse students.
I think these punishments are commonly decided by administrators, not teachers. The teacher just reports them up the chain for misbehavior.
Suspension and expulsion are becoming embroiled in the anti-racism crusade due to some high-profile incidents, so blunt laws are being written to outlaw them altogether.