The ridges (edge reeding) don’t serve any functional purpose anymore. It wouldn’t make sense to clip or file metal from a clad quarter or dime. The history behind it is very interesting though. If you want to get into the weeds, it’s worth googling the topic of coin clipping in England. This was something that was legally punishable by death or imprisonment, but was done by lots of people anyway.
Clipping was done frequently enough to seriously affect the integrity of the country’s currency. Hopefully murder isn’t being done that frequently, although it’s certainly more frequent than any of us would like. There have even been hoards discovered of coin clippings versus the coins themselves.
I believe the concern was people clipping silver and gold coins, hence the need for a reeded/decorated edge. I don't think this was an issue with copper (although the colonial experts can correct me if I'm wrong).
There was also a practice called sweating. It's a bit hard to see how that was prosecuted -- "Yes, I kept my coins in a bag. What else would I keep them in? Yes, it got bounced around as I traveled, as does anything a horse carries. And, yes, I saved the gold dust I found in the bag afterward -- what should I do, throw it away?"
