You'll find a lot of reasons why someone with BPH or prostatitis would prefer to take prostate supplements. Not just for their urinary "plumbing" and symptoms, ProstaMend [look at here now] but because they are able to help with other health issues, too.
But, you shouldn't just rely on them for results.
In reality, in many cases making dietary changes are able to do even more for the symptoms of yours than the prostate supplements could.
Consider, for instance, this sixty year old male in Texas I know about who started out taking a combo of pygeum (an incredibly potent prostate health supplement) and saw palmetto. The problem of his was purely urinary. He started noticing (like a lot of males at his age do) that the stream of his was weakening.
Put simply, the stream of his was becoming more of a "trickle" than a stream.
And, naturally, he was becoming concerned about it.
So he doubled up on his health supplements.
That seemed to help a bit of, but didn't really solve the problem to the satisfaction of his at all.