Funny you should say that, ive seen them save many turbos. Saying they dont do much is really just plain stupidity/ignorance. Having a filter, regardless if its a 15 micron oil filter or a 45 micron fuel filter is better then having nothing. If you blow your motor up, or you somehow get a large about of foreign particles in the oil, atleast you will save the turbo.
At the end of the day, either option is viable.