Fear not your sniffers, dear WiFi folk. For they are your path to the truth.
I had a conference call today and the topic of carrier devices (smartphones, 3G/4G enabled tablets, etc.) on Wi-Fi networks came up. The person on the other end needed to make sure that his WiFi devices were optimized for a variety of different WLAN infrastructures.
My first reaction (as is my first reaction to most WiFi related topics) was to sniff. First set up the infrastructure. Then use the device (which could mean connecting, roaming or running an app). Then sniff what's happening.
His reaction to my sniffing idea was pretty negative. Their testing procedures are basically trial & error. Set up the WLAN, then connect the device and then document what the user experience is. If the user experience stinks, then make a change. He was a sniffophobe.
I get why people are sniffophobes. WiFi sniffers can be expensive and difficult to learn. The idea that you're going to have to train a large group of people to understand sniffing software before you even run your first test may seem daunting.
Sniffers are worth it because actions speak louder than words. The "words" of a device are its GUI. The "actions" of a device are its WiFi frames. Sniffing frames reveals the truth. If you device is too sticky or too slow or too jumpy or too whatever, then those WiFi frames will usually reveal it. If you don't have those frames, then you might be seeing a problem that is caused by something that you are unaware of.
WiFi sniffing is a specialized skill. But for the people who really need to know details on how a device works or why a connection is unstable or if performance will hold up under stress, sniffing is worth it. Try to avoid letting sniffophobia keep you from getting the information you need.