I have been picking them off as soon as they go red and have used them to grow new plants. They are very sticky when you open the berries.
On Gardeners World's allotment it was said that the best thing to do with any which started to fruit was to pull up the entire stem as soon as the it was identified as female.
I can see what delboy means about growing all over the place if you leave them because they seem to be easy to propagate.
To my knowledge there is no use for them as being useful to us, medically but you could always pick them off and put them on the bird table, the birds are worth feeding over winter.