My two cents on this subject is that they are worth having but not essential. Subjectively, I find it much easier to pick up other aicraft with strobes and would be very happy if the white aeroplane I fly was equipped with strobes. In ten years of flying I have had three close calls, at least one of which would have been much less likely had I a strobe equipped aeroplane.
As other posters have said; They only need to save your life once to be worth having.