Attorney: "Why were you carrying a ball peen hammer in a kydex sheath? Clearly you weren't going to use it as tool since it wasn't in a tool belt." It'll snowball from there. Canes, knives, guns, and walking sticks are better options since it's easy to explain that "I carry a gun/knife for self defense" or "I used my cane/walking stick because I had it with me and was using it to help me walk".
Hammers are commonly used for B&E in my neck of the woods and even if they weren't, it's not as easy to articulate some contrived reason to a jury as to why you're carrying a hammer (outside of being a carpenter and even then, why are you concealing it instead of carrying it on your tool belt?) with other tools/weapons are available.