Apple doesn’t have to promote their use in finding / recovering stolen items. Some people will simply think that way, either because they’ve had certain things stolen in the past or because they are simply afraid a theft could happen.
I personally don’t lose things like my car keys or wallet, or briefcase for that matter. But I have had bicycles stolen, so that was one of the things I thought about using the AirTag for (hiding on the bikes). Is the market really that big for people who lose or misplace things on such a regular basis that they need AirTags?