I use a cow call more often mule deer hunting than anything else. Time after time it is ideal to stop a deer from walking without scaring the beegeezers out of them. The fallacy of deer just standing around giving unlimited time for a shot costs a lot of deer every year. Some guys can do a good job of making a sound with their own mouth, but nothing I have tried is as effective and easy as a cow call.
I’ve had a deer at 70 yards going full speed stop at a moderately loud “mew” long enough for a shot. We all know deer often stop and look back before going over a ridge and a cow call can get them to stop a second time. It can get a bedded deer to stand up, or get a deer to turn a little to get a better look at his head gear.
The kid in me also likes anything that plays with the brains of animals. Over the years I’ve had a lot of fun with young deer testing the most effective ways to use it.