How many points UB has speciality of UB
If I’m understanding your question correctly, you seem to misunderstand how acupuncture works generally. It is not a point - to - condition/symptom system - i.e. this point is for “x”, this point is for “y”. While there are a few empirical points that tend to be used like that - even with those points there are many other uses in combination with other points. For the basics see “acupuncture point treatment guidelines” and “treating the cause vs. the symptoms”.
I think what you are interested in is what are called shu points - details here. In that section you will see that UB 28 is the “bladder shu” point. But it is not used as much for the physical bladder in western terms as it is the bladder in Chinese Medicine terms and it’s relation to other systems in the body. While it is an important point for urinary/bladder issues such as UTI’s, etc. it is also used for “For damp-heat anywhere in the body - diarrhea, constipation, sore back, infections and/or swellings in the lower warmer.”