My take on them is that they are beneficial if you are using your compost piles as home waste management center -- seriously reducing your carbon footprint -- because they can handle the things that are normally considered uncompostable.
HOWEVER, they eat most everything up so you will get much less (I think maybe only 25%?) of COMPOST as final product, so if you want to MAKE compost, they are not very useful.
On the ther hand, people like Eric/DoubleDog Farm who could use the BSF pupae as final product for feeding poultry or fish as protein source would find them to be excellent self sufficient waste-to-feed converters, especially since they can then harvest eggs, chicks, or meat of the livestock for later human consumption or sale.
If you keep pets that would eat the larvae/pupae and normally BUY food for them, it might be something to consider too. Another way to use BSF is to maintain a separate pile/bin for pet wastes to be consumed by the BSF. (I suppose you wouldn't use larvae/pupae as feed in this case -- maybe just let them repeat their life cycle in the bin through the season....)
I haven't found any in my compost yet so I haven't been inclined to experiment, though. In my area, I believe they won't be able to overwinter in the outside bin either. Hopefully more people who have tried raising BSF will comment.
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