I use them frequently when I have fry that have outgrown BBS. If I try to switch to non-live foods at that stage I lose more of the population to cannibalism than w/ the worms.
Shrimp & beef heart? Do you cook these, or put them in the tank raw? If raw, does this make the water dirty? I'm even afraid to put frozen brine shrimp in my tank because of the raw meat bacteria...
I would have to say no on the raw beef heart at least. i've not needed to use it myself but i've read of several people that had planaria outbreaks shortly after adding it to tank.
I've also read people fishless cycle a tank with a piece of raw shrimp.
Raw shrimp make up a large portion of my fishes' diets. I've used beefheart in the past, but no longer do so. (I never had a problem with it, I just found it time-consuming to process and ultimately unnecessary.)